RAPID   METHODS 

FOR  THE 

CHEMICAL   ANALYSIS 


OF 


SPECIAL  STEELS,  STEEL-MAKING 
ALLOYS,  AND    GRAPHITE 


BY 

CHARLES  MORRIS  JOHNSON,  PH.M. 

it 

CHIEF  CHEMIST  TO  THE  PARK   STEEL  WORKS   OF   THE   CRUCIBLE 
STEEL  COMPANY  OF   AMERICA 


SECOND  EDITION,  REWRITTEN 

FIRST   THOUSAND 


NEW    YORK 

JOHN  WILEY  &  SONS,  INC. 

LONDON:    CHAPMAN   &   HALL,  LIMITED 
1914 


COPYRIGHT,  1909,  1913,  1914 

BY 
CHARLES  MORRIS  JOHNSON 


First  Edition  Entered  at  Stationers'  Hall 
Second  Edition  Copyrighted,  1914,  in  Great  Britain 


Stanhope  flbress 

F.    H.  GILSON   COMPANY 
BOSTON,  U.S.A. 


PREFACE. 

IN  offering  this  little  volume  the  author  desires  to  call  atten- 
tion to  the  portions  of  it  that  he  has  worked  out  in  his  own  way 
and  that  are,  as  far  as  he  is  aware,  new  features,  (i)  A  quali- 
tative test  for  titanium  in  the  presence  of  "vanadium.  (2)  The 
annealed  test  for  chromium  in  steel.  (3)  The  test  for  annealing 
in  steel.  (4)  The  pouring  of  the  indicator  into  the  solution  when 
titrating  for  vanadium  and  chromium  in  steel,  in  the  presence 
of-  either  or  both  elements.  (5)  The  determination  of  small 
amounts  of  copper  and  nickel  in  steel  and  ferro-vanadium  by 
first  separating  the  copper  and  nickel  from  the  bulk  of  the  iron 
and  vanadium  by  means  of  potassium  ferricyanide.  (6)  The 
EXACT  determination  of  phosphorus  in  ferro-vanadium,  demon- 
strating that  as  little  as  one-eighth  of  the  actual  phosphorus  may 
be  obtained  by  the  ordinary  processes.  (7)  The  application 
of  the  new  heating  wire  to  a  combustion  tube.  (8)  The  modified 
method  for  higher  per  cents  of  nickel.  (9)  The  determination 
of  silicon  carbide  in  old  plumbago  crucibles  and  ITS  EXISTENCE 
THEREIN.  (10)  The  automatic  laboratory  still,  (n)  The  simple 
laboratory  method  for  making  clay  combustion  boats.  (12) 
The  method  for  annealing  Hadfield's  steel.  (13)  The  method 
for  the  rapid  volumetric  determination  of  manganese  in  the 
presence  of  iron,  calcium  and  magnesium,  by  means  of  potassium 
ferricyanide.  (14)  The  new  form  of  potash  absorption  and 
weighing  apparatus  for  carbon  dioxide.  (15)  The  new  form 
of  combustion  train. 

The  test  for  annealing  in  steel  was  first  suggested  to  the  writer 
about  ten  or  twelve  years  ago  by  Dr.  E.  S.  Johnson.  The  author 
has  since  studied  it  in  its  application  to  all  kinds  of  alloy  steels. 

It  is  the  author's  hope  that,  at  least,  some  of  the  information 
contained  in  this  book  may  prove  as  helpful  to  its  readers  as  it 
has  to  him. 

PITTSBURGH,  PA.,  July  i,  1908. 

iii 


INTRODUCTION  TO  THE   SECOND   EDITION. 

The  author  wishes:  ist.  —  To  devote  the  preface  of  the  second 
edition  of  his  book  to  emphasizing  the  generalization,  or  rule 
which  he  believes  should  guide  those  who  wish  to  experiment  in 
the  alloying  of  iron  with  other  elements:  The  general  statement 
can  be  expressed  as  follows:  If  iron  be  combined  by  fusion  with 
notable  quantities  of  an  element  whose  melting  point  is  very 
much  below  that  of  iron,  the  tendency  is  to  produce  a  metal  of 
inferior  physical  properties,  but  if  iron  be  combined  with  an 
element  whose  melting  point  is  nearly  that  or  higher  than  that  of 
iron,  then  the  tendency  is  to  produce  a  metal  of  superior  physical 
properties. 

It  would  seem  safe  to  add  that  the  lower  the  melting  point 
of  the  non-ferrous  element,  the  more  inferior  the  resultant 
metal  and  the  higher  the  melting  point  of  the  non-ferrous  con- 
stituent, the  more  valuable  the  properties  of  the  resulting  metal. 

The  common  enemies  of  steel  are  phosphorus  (m.  p.  44°  C.) 
and  sulphur  (m.  p.  114  to  120°  C.)  Much  has  been  written 
about  the  evil  effects  of  nitrogen  in  steel;  with  a  melting  point  of 
—  214°  C.,  this  is  to  be  expected.  Tin  alloys  readily  with 
iron  and  the  writer  knows  from  his  own  experiments  that  0.400 
per  cent  of  tin  causes  in  steel  both  cold  and  red  shortness.  Its 
melting  point  is  232°  C.  Lead  (m.  p.  326°  C.),  bismuth  (m.  p. 
270°  C.)  and  cadmium  (m.  p.  321°  C.)  are  to  be  feared  as  much  as 
tin.  Arsenic  (m.  p.  480°  C.  under  pressure),  zinc  (m.  p.  419°  C.), 
antimony  (630°  C.)  and  aluminum  (658°  C.)  cannot  be  expected 
to  produce  desirable  alloys  with  iron.  Copper,  whose  melting 
point  (1083°  C.)  is  437°  C.  below  the  melting  point  of  iron 
(1520°  C.)  causes  notable  red  shortness  when  present  to  the 
extent  of  i  per  cent  and  less,  depending  on  the  amount  of 
carbon,  etc.,  present. 


VI  INTRODUCTION  TO  THE   SECOND   EDITION 

The  beneficial  results  of  alloying  iron  with  elements  near  its 
own  melting  point,  such  as  chromium  (1505°  C.),  nickel  (1450° 
C.),  cobalt  (1490°  C.),  are  matters  of  everyday  metallurgical 
knowledge.  Vanadium  with  a  still  higher  melting  point,  around 
1700°  C.,  is  famous  for  its  useful  combinations  with  iron  in 
conjunction  with  chromium  or  tungsten,  or  both.  Great  claims 
are  made  for  the  beneficial  effect  of  combining  titanium  with 
iron  but,  as  yet,  in  quantities  of  less  than  i  per  cent.  The 
author  ventures  the  prediction,  that  this  element  will  be  com- 
bined with  iron  in  greater  quantities  producing  results  that  will 
justify  the  expense.*  Advancing  still  higher  in  the  scale  of 
melting  point,  molybdenum  stands  out  as  an  element  that  has 
been  alloyed  with  iron  in  notable  quantities  with  splendid  results 
but  its  high  price  has  caused  its  replacement  by  the  cheaper 
element,  j  tungsten  whose  still  higher  melting  point  of  3000°  C. 
makes  it  the  logical  superior  of  molybdenum  with  a  melting 
point  approximating  2500°  C. 

Last  of  all  we  come  to  carbon  which  does  not  melt  at  all  but 
finally  succumbs  to  the  temperature  of  the  electric  arc,  by 
volatilizing  around  3500°  C.  This  most  wonderful  of  all  of  the 
elements  can  be  truly  styled  the  exponent  and  intensifier  of  all 
the  virtues  that  steel  possesses. 

2nd.  —  Attention  is  directed  to  the  author's  method  for  the 
determination  of  phosphorus  in  tungsten  bearing  materials. 

yd.  —  To  his  method  for  the  determination  of  tungsten  in 
its  ores. 

4th.  —  To  his  method  for  the  determination  of  sulphur  in 
alloy  steels  by  heating  the  insoluble  carbides,  which  carry  the 
major  part  of  the  sulphur,  to  a  yellow  heat  in  a  stream  of  acid  — 
carrying  hydrogen,  evolving  the  sulphur  from  sulphates  such  as 
barium  sulphate  in  the  same  manner,  as  hydrogen  sulphide. 

$th.  —  To  his  modification  of  Brunck's  method  for  nickel  in 
steel. 

*  The  experimenter  should  insist  on  alloys  that  are  free  from  low  melting 
elements  such  as  aluminum  or  any  of  the  above;  as  free  as  at  all  possible,  or 
otherwise  he  may  condemn  the  high  melting  elements  for  the  shortcomings  of  low 
ones  that  he  has  added  unawares. 


INTRODUCTION  TO  THE   SECOND   EDITION  Vll 

6th.  —  To  his  method  for  the  titration  of  iron  or  vanadium,  or 
both,  in  the  presence  of  uranium,  getting  the  latter  by  difference, 
all  in  the  one  operation,  after  having  weighed  all  as  total  oxides. 

7//z.  —  To  his  method  for  the  determination  of  uranium  in 
ores,  in  ferro-uranium  and  in  steels. 

Sth.  —  To  the  complete  methods  for  the  analysis  of  cobalt 
steels  and  cobalt  metals. 

gth.  —  To  the  author's  investigation  of  the  cause  of  bark  in 
pipe-annealed  steel. 

loth.  —  To  his  tapered  clay  combustion  tube,  eliminating  all 
rubber  stoppers. 

nth. — To  his  milling  machine,  one  piece  nichrome  triangle 
and  the  plan  and  views  of  the  laboratory  rooms. 

1 2th.  —  The  second  edition  contains  200  pages  of  additional 
material. 

i$th.  —  The  author  wishes  to  thank  all  of  those  who  have  made 
the  second  edition  of  this  book  possible  by  investing  in  the  first 
edition. 

He  has  endeavored  to  bring  his  book  up  to  the  latest  and 
best  analytical  practice  in  iron,  steel  and  its  alloys.  He  has 
added  chapters  on  the  testing  of  lubricating  oils,  coal,  iron  ores, 
fluorspar,  limestone,  sand  and  fire-brick  to  save  some  of  his 
younger  readers  the  time  he  has  spent  in  wading  through  the 
maze  of  literature  on  some  of  these  topics,  especially  the  first  one. 

PITTSBURGH,  PA.,  Oct.  10,  1913. 


CONTENTS. 


CHAPTER  PAGES 
I.   Qualitative  tests  for  chromium,  vanadium,  titanium,  mo- 
lybdenum, tungsten,  nickel,  and  cobalt i  to  3 

II.  Analysis  of  vanadium  steel  and  ferro- vanadium 4  to  42 

III.   Analysis  of  ferro-titanium,  titanium  steel,  and  basic  slag 

containing  titanium 43  to  67 

IV- 1.  Analysis  of  tungsten  powder.  Determination  of  oxygen 
in  metallic  tungsten  powder  and  steel.  Determina- 
tion of  tin  in  metallic  tungsten 68  to  89 

IV-2.   Sampling  of  tungsten  ores.     Determination  of  tungsten  in 

tungsten  ores 90  to  97 

IV-3.  First  method  for  tungsten  in  steel.  Gravimetric  method 
for  sulphur  in  chromium-tungsten  steel.  Evolution 
method  for  sulphur  in  alloy  steels  by  ignition  of  the 
insoluble  residue,  at  a  yellow  heat  in  acid-carrying 
hydrogen 98  to  107 

IV-4.  Analysis  of  low  per  cent  tungsten  steels  and  slag  contain- 
ing chromium,  tungsten,  and  vanadium 108  to  114 

V-i.   Analysis  of  molybdenum  powders 115  to  121 

V-2.   Analysis    of    ferro-molybdenum    and    ferro-molybdenum- 

tungsten 122  to  127 

V~3.   Determination  of  molybdenum  in  molybdenum  ore 128 

V-4.   Analysis  of  tungsten-molybdenum  steels 129  to  133 

Y-S.   Determination  of  tin  and  bismuth  in  plain  and  alloy  steels    134  to  135 

VI-i.   Analysis  of  ferro-chromium,  chromium  ore,  and  carbonless 

chromium 136  to  143 

VI-2.   Analysis  of  chrome  cement 144  to  145 

VII.  Aluminum  in  steel.  The  determination  of  small  amounts 
of  aluminum,  uranium,  vanadium,  chromium,  and  tita- 
nium in  steel 146  to  148 

VIII-i.   Copper  in  steel  and  pig  iron 149  to  153 


X  CONTENTS 

CHAPTER  PAGES 

VIII-2.  The  separation  of  copper  and  nickel  from  iron  and  vanadium 

by  potassium  ferricyanide 154  to  156 

VIII-3.   The  determination  of  copper  in  metallic  copper 157  to  163 

IX-i.  Rapid  determination  of  nickel  in  the  presence  of  chro- 
mium, iron,  manganese,  vanadium,  and  tungsten,  by 
the  author's  modified  cyanide  method,  by  Brunck's 
method  and  by  a  modification  of  Brunck's  method 164  to  177 

IX-2.   The  analysis  of  nickel-chromium  alloy 178  to  182 

1X-3.   The  analysis  of  nickel-copper-iron  alloy 183  to  187 

X-i.   The  analysis  of  ferro-manganese 188  to  192 

X-2.  A  volumetric  method  for  manganese  in  the  presence  of  iron, 
calcium,  and  magnesium  by  titration  with  potassium  fer- 
ricyanide. Also  the  same  titration  in  the  absence  of 
iron 193  to  202 

XI-i.   The  determination  of  carbon  in  iron,  steel,  alloys,  graphite, 

etc.,  by  direct  ignition  with  red  lead 203  to  220 

Laboratory  milling  machine  for  sampling  steel.     Segrega- 
tion test  by  acid  etching 220  to  223 

XI-2.  The  determination  of  carbon  in  steel,  ferro-alloys,   and 

graphite  by  means  of  an  electric  combustion  furnace 224  to  232 

By  means  of  a  compressed  air  and  gas  furnace 232  to  240 

XI~3.   The  elimination  of  rubber  stoppers  from  the  tapered  clay 

combustion  tube 243  to  245 

XI-4.   The  determination  of  carbon  in  plain  steel  by  solution  of 

the  steel  in  copper  and  potassium  chloride 246  to  250 

XI-5.   The  determination  of  graphite  in  iron,  and  graphitic  carbon 

in  steel 251 

XII-i.   Carbon  in  steel  by  color 252  to  256 

XII-2.   The  determination  of  phosphorus  in  pig  iron,  steel,  and 

washed  metal 257  to  264 

XII-3-    The  analysis  of  ferro-phosphorus 265  to  268 

XII-4.   The  determination  of  sulphur  in  steel,  muck  bar,  pig  iron, 

and  washed  metal 269  to  275 

XII-5.   The  determination  of  manganese  in  steel,  pig  iron,  and 

chrome  steel  276  to  280 

XII-6.  The  determination  of  manganese  in  24  per  cent  nickel  steel    281  to  282 

XII-7.   The  determination  of  manganese  in  steel  by  the  persul- 
phate method 283  to  284 

XII-8.  The  determination  of  silicon  in  pig  iron  and  steel 285  to  286 


CONTENTS  XI 

CHAPTER  PAGES 

Xll-g.  The  analysis  of  calcium-electrosilicon 287  to  288 

XIII-'i.  The  determination  of  uranium  in  ferro-uranium,  carno- 
tite  ore,  in  mixtures  of  iron,  uranium,  aluminum,  and  va- 
nadium, and  in  steel  containing  tungsten,  chromium, 
vanadium 289  to  300 

XIII-2.   The  determination  of  vanadium  in  sandstones  containing 

carnotite,  roscoelite,  or  calcium  vanadate 300  to  302 

XIV-i.  The  qualitative  and  quantitative  analysis  of  cobalt  and 
nickel-cobalt  steel.  The  electrolytic  determination  of 
cobalt  and  nickel  in  ferro-cobalt  and  cobalt  powder.  .  .  .  303  to  323 

XV.   The  determination  of  nitrogen  in  steel 324  to  328 

XVI.   The  analysis  of  graphite  and  graphite  crucibles 329  to  338 

XVII-i.   The  annealing  of  steel 339  to  346 

XVII-2.  Further  annealing  temperatures  and  the  formation  of  de- 
carbonized surface  on  steel . 347  to  355 

XVIII-i.  The  complete  analysis  of  limestone  and  magnesite 356  to  359 

XVIII-2.  The  complete  analysis  of  bottom  sand  and  fire  brick 360  to  366 

XVIII-3.  The  analysis  of  iron  ore 367  to  374 

XVIII-4.  The  analysis  of  fluorspar 375  to  384 

XIX-i.  The  testing  of  lubricating  oils 385  to  397 

XIX-2.  The  testing  of  coal  and  coke 398  to  403 

XX-i.   The  percentage  reduction  of  a  substance  in  solution  to 

any  desired  percentage 404  to  409 

XX-2.   Plan  and  views  of  chemical  laboratory  for  steel  works 

practice 410  to  418 

XX-3.  The  making  and  repairing  of  laboratory  electric  furnaces. 
A  one-piece  nichrome  triangle.  A  sanitary  washing 
bottle 419  to  422 

XX-4.  An  automatic  steam  water  still 423  to  425 

XX-$.  The  making  of  clay  combustion  boats 426  to  428 


ERRATA 

Page  40,  ist  and  2nd  lines  from  the  bottom,  0.00847  should  read  0.000847. 
"  377>  4th  line  from  the  bottom,  "  carbonate  "  should  read  "  chloride." 


ANALYSIS    OF    SPECIAL    STEELS,    STEEL- 
MAKING   ALLOYS    AND    GRAPHITE. 


CHAPTER  I. 

QUALITATIVE  TESTS  FOR  CHROMIUM,  TUNGSTEN, 
NICKEL,  MOLYBDENUM,  ETC. 

DISSOLVE  0.200  gram  of  the  sample  with  5  c.c.  i  :  3  sul- 
phuric acid  in  152.4  (6  inches)  by  16  mm.  test  tube.  Also 
0.200  gram  of  a  plain  carbon  steel  in  the  same  way.  Place 
the  two  tests  in  boiling  water  for  a  half  hour. 

The  plain  carbon  steel  will  be  free  from  black  sediment  and 
practically  water  white  as  to  color.  If  the  unknown  contains 
as  little  as  0.2  or  0.3  per  cent  of  chromium  it  will  look  distinctly 
greener  than  the  known  steel.  Nickel  also  produces  this  effect, 
but  the  color  is  not  so  marked. 

If  the  steel  has  o.ioo  to  0.3  per  cent  of  tungsten  a  black  insol- 
uble residue  will  be  found  in  the  bottom  of  the  tube.  This 
black  sediment  forms  also  with  similar  amounts  of  molybdenum 
and  phosphorus.  But  on  addition  of  i  c.c.  of  1.20  nitric  acid 
to  such  a  solution  the  black  entirely  disappears  if  due  to  the 
presence  of  the  two  last  named  elements.  The  black  precipi- 
tate, if  caused  by  a  small  quantity  of  tungsten,  on  addition  of 
the  nitric  acid,  changes  to  a  yellow  one.  If  the  amount  of 
the  latter  is  small  it  is  better  to  put  the  test  tube  back  on  the 
water  bath  and  permit  the  tungstic  acid  to  settle  for  two  hours, 
when  it  can  be  seen  plainly  as  a  yellow  spiral  thread  rising  up 
through  the  solution  by  giving  the  test  tube  a  rotary  motion. 
The  black  residue  of  phosphide  can  be  recognized  by  filtering 
it  out  and  dropping  i  :  i  hydrochloric  acid  on  it,  when  the 
characteristic  odor  of  phosphine  is  obtained.  Or  it  can  be 


2  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

dissolved  off  the  filter  with  1.20  nitric  acid  and  the  filtrate 
precipitated  with  molybdate  solution  after  boiling  it  with  a 
slight  excess  of  potassium  permanganate.  Finish  as  in  plain 
steel  to  get  the  yellow  precipitate.  If  steels  are  quite  high 
in  silicon,  the  silicic  acid  and  the  carbon,  together,  produce 
black  flakes  that  float  about.  They  turn  to  white  ones  on 
being  heated  with  1.20  nitric  acid  on  a  water  bath  for  an  hour 
or  two. 

The  annealed  test  for  chromium  is  given  under  "Annealing 
of  Steel."  (See  page  345.) 

MOLYBDENUM. 

A  further  qualitative  test  for  the  latter  element  is  as  follows: 
Dissolve  0.500  gram  of  sample  in  25  c.c.  of  i  :  i  hydrochloric 
acid.  Boil  till  action  ceases,  using  a  254  by  25.4  mm.  (10  by 
i  inch)  tube.  Heat  further  with  2.5  grams  of  potassium  chlo- 
rate until  a  clear  solution  has  been  obtained  or  the  residue,  if 
any,  is  a  bright  yellow.  Add  an  equal  volume  of  water.  Filter 
without  washing.  Dissolve  10  grams  of  potassium  hydroxide 
in  10  c.c.  of  water.  Add  this  to  the  filtered  solution.  Boil  for 
five  minutes.  Filter.  Do  not  wash.  Pour  8  c.c.  of  this  filtrate 
into  a  254  by  25.4  mm.  tube.  Add  cone,  hydrochloric  acid 
until  crystals  form.  Dilute  with  water  to  30  c.c.  Add  a  few 
grains  of  granulated  tin.  Heat  to  the  first  indication  of  boiling; 
remove  from  heat  immediately  and  cool.  Add  to  the  cold 
solution  2  c.c.  of  potassium  sulphocyanate.  A  light  brownish 
red  indicates  0.2  or  0.3  per  cent  of  molybdenum.  A  distinct 
red  indicates  i  to  2  per  cent  and  a  deep  red  higher  amounts 
of  molybdenum.  This  is  a  fine  test,  but  if  the  mistake  is  made 
of  boiling  the  solution  too  long  with  the  tin  scarcely  any  color 
is  obtained.  Bring,  therefore,  to  incipient  boiling,  only,  after 
putting  in  the  grains  of  tin.  Then  remove  at  once  from  the 
fire  and  test  with  the  KCNS  as  already  described.  For  nickel 
the  quantitative  analysis  as  given  on  page  164  is  so  rapidly 
carried  out  that  it  constitutes  an  easy  qualitative  test  also. 

For  qualitative  tests  for  titanium  and  vanadium  see  page  4. 


QUALITATIVE  TESTS  FOR   CHROMIUM,  TUNGSTEN,   ETC.       3 

For  qualitative  tests  for  copper  in  steel  see  page  151.  For 
qualitative  tests  for  copper  in  ferro-vanadium  see  page  154. 
For  qualitative  test  for  nickel  in  steel  see,  also,  page  10. 

Qualitative  test  for  cobalt:   (See  page  303.) 

Qualitative  test  for  nickel:  Dissolve  0.5  gram  of  the  steel 
as  given  for  vanadium  on  page  4.  When  the  red  fumes 
are  gone  cool;  add  2  grams  of  citric  acid  and  then  ammonia 
until  the  solution  is  ammoniacal  and  clear.  Now  introduce  a 
solution  of  dime  thy  Iglyoxime  of  the  strength  given  on  page  176. 
A  scarlet  precipitate  will  form  if  nickel  is  present.  See  also 
page  303  if  the  chemist  wishes  to  first  remove  the  iron  before 
adding  the  " dimethyl"  which  is  a  better  way  if  the  per  cent 
of  nickel  is  very  small. 

Qualitative  test  for  titanium  in  the  presence  of  vanadium: 
Dissolve  the  steel  as  for  vanadium  as  given  on  page  4  but  in 
a  small  boiling  flask,  using  0.5  gram  of  sample.  Then  perox- 
idize  as  described  on  page  23  taking  proportionately  smaller 
amounts  of  the  sodium  peroxide  and  carbonate.  Redissolve 
the  iron  hydroxide,  after  washing  it  with  peroxide  water,  and 
peroxidize  again,  and  so  on  until  some  of  the  filtrate  from  the 
iron  hydroxide  no  longer  gives  a  vanadium  test  with  H2O2  on 
being  boiled  down  to  one-half  with  twice  its  bulk  of  cone,  nitric 
acid.  The  iron  hydroxide  can  then  be  dissolved  with  1.20  nitric 
acid  and  be  tested  with  hydrogen  peroxide  for  Ti.  The  iron 
hydroxide  will  contain  all  of  the  Ti,  free  from  V. 


CHAPTER  II. 

*  ANALYSIS  OF  VANADIUM  STEEL  AND  FERRO-VANADIUM. 

THE  determination  of  vanadium  in  the  presence  of  tungsten, 
titanium,  chromium,  nickel,  manganese,  silicon,  molybdenum, 
copper  and  aluminum  has  been  studied  by  the  author.  It 
has  been  the  latter's  aim  to  produce  modified  methods  that 
combine  speed,  simplicity  and  accuracy.  The  underlying 
reactions  are  well  known  and  have  been  variously  applied  by 
different  chemists. 

QUALITATIVE  TESTS. 
Absence  of  Titanium. 

A  qualitative  test  for  vanadium  can  be  completed  in  a  half 
hour  or  less,  even  in  the  presence  of  4  per  cent  of  chromium, 
although  there  be  but  0.05  per  cent  of  vanadium  in  solution. 
Dissolve  0.500  gram  of  steel  in  a  254  by  25.4  mm.  test  tube 
(10  by  i  inch)  in  10  c.c.  i  :  3  sulphuric  acid,  heating  until  action 
ceases,  adding  a  little  water,  if  necessary,  to  dissolve  any  sul- 
phate of  iron  that  may  separate  during  the  boiling.  5  c.c.  of 
concentrated  nitric  acid  are  used  to  oxidize  the  iron  and  hypo- 
vanadic  acid.  Heating  is  continued  until  red  fumes  disappear. 
If  tungsten  be  present,  filter  through  paper.  Filter  without 
washing.  Pour  some  of  the  filtered  or  unfiltered  fluid,  as  the 
case  may  be,  into  two  152  by  16  mm.  test  tubes,  allowing  about 
5  c.c.  of  the  solution  to  each  tube.  To  one  of  these  portions 
add  5  c.c.  of  sodium  peroxide  dissolved  in  dilute  sulphuric 
acid.  To  the  other  add  5  c.c.  of  water.  The  portion  to  which 
the  sodium  peroxide  was  added  assumes  a  reddish  brown  shade 
if  vanadium  is  present. 

*  From  a  paper  read  before  the  Pittsburgh  section  of  the  American  Chemical 
Soc.,  Jan.  23,  1908. 

4 


ANALYSIS  OF   VANADIUM   STEEL  AND   FERRO-VANADIUM       5 

If  there  be  enough  chromium  to  give  the  solution  a  dark 
green  tint,  then  hold  the  tubes  against  an  illuminated  white 
shade.  The  vanadic  solution  containing  peroxide  will  plainly 
show  a  browner  tint  than  its  mate,  to  which  no  peroxide  was 
added.  The  white  shade  greatly  lessens  the  interference  of 
the  chrome  green.  The  peroxide  is  prepared  by  dissolving  3.5 
grams  of  sodium  peroxide  in  125  c.c.  of  i  :  3  sulphuric  acid  and 
diluting  with  distilled  water  to  500  c.c.  Add  the  water  last, 
when  preparing  the  peroxide  solution. 

QUALITATIVE  TEST  FOR  VANADIUM  IN  THE  PRESENCE 
or  TITANIUM. 

Recent  works  on  steel  analysis  give  the  peroxide  qualitative 
test  for  vanadium  and  titanium  but  dismiss  the  subject  with 
comment  that  either  element  interferes  with  the  qualitative 
test  for  the  other.  The  writer  has  overcome  this  interference 
by  the  use  of  ferrous  ammonium  sulphate  which,  as  far  as  he 
is  aware,  is  a  new  departure.  By  this  means  as  little  as  o.ioo 
per  cent  of  titanium  can  be  detected  without  the  least  difficulty 
in  the  presence  of  ten  times  as  much  vanadium,  in  spite  of  the 
fact  that  the  color  of  vanadium  with  peroxide  is  much  stronger 
than  that  of  titanium  and  hydrogen  peroxide.  The  principle 
involved  is,  briefly,  that  ferrous  ammonium  sulphate  discharges 
the  brick  red  color  obtained  by  mixing  a  vanadic  solution  with 
hydrogen  peroxide  more  quickly  than  it  does  the  yellow  shade 
of  the  titanic  acid  and  H2O2.  An  extract  from  the  author's 
experimental  records  illustrates  the  procedure.  The  regular 
ferrous  ammonium  sulphate  standard  as  given  for  vanadium 
titrations,  later  in  this  chapter,  was  used  for  the  experiments 
(A)  and  (B)  and  other  similar  ones. 

Experiment  A  was  repeated  with  gradual  increase  of  vanadium 
up  to  i  per  cent  V,  keeping  the  titanium  still  at  0.13  per  cent, 
with  results  identical  with  the  above,  so  that  even  with  ten 
times  as  much  vanadium  the  latter  was  decolorized  more  quickly, 
and  was  slower  in  regaining  color,  when  peroxide  was  again 
added,  than  the  titanium. 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 
EXPERIMENT  A. 


Reagent. 

Result. 

Vtixture  No.  i. 
500  mg.  plain  carbon 
steel,  8  mg.  8%  Fer- 
ro    Ti,    10    mg.    of 
21.8%  Ferro  V,  or 
o.  13%  Ti  and  0.436% 

ist,  added  5  c.c.  YlzOz 
solution. 
2d,  added  5  c.c.  ferrous 
sulphate. 
3d,  added  5  c.c.  more 
of  sulphate. 
4th,    added    5    c.c.    of 
H2O2  again. 

Brick  red  color. 

Faded  to  distinct  yel- 
low. 
Decolorized. 

Return  of  distinct  yel- 
low. 

Mixture  No.  2. 
1500  mg.  plain  carbon 
steel,     10     mg.     of 
22.0%  Ferro  V,   or 
0.44%    V.     No    Ti 
added. 

ist,  same  as  above. 
2d,  as  in  2d  No.  i. 

3d,  as  in  3d  No.  i. 
4th,  as  in  4th  No.  i. 

Brick  red  color. 
Brick    red    nearly    all 
gone. 
Brick  red  all  gone. 
No  return  of  red  color 
until  10  minutes  had 
elapsed. 

A  mixture  containing  i  per  cent  V  with  0.500  gm.  plain  steel 
behaved  in  the  same  manner  as  given  in  B.  Vanadium  grad- 
ually regains  its  red.  A  glance  at  the  tabulation  shows  that, 
if  the  chemist  wishes  to  detect  titanium  in  the  presence  of  vana- 
dium, he  need  only  resort  to  the  simple  expedient  of  adding 
slowly,  a  c.c.  at  a  time,  the  ferrous  ammonium  sulphate  stand- 
ard to  the  qualitative  vanadium  test.  If  it  gradually  fades 
from  a  brick  red  to  a  bright  yellow  then  titanium  is  surely 
present.  But  if  the  red  or  brown  tint  fades  directly  to  a  nearly 
colorless  condition  without  showing  a  clear  bright  yellow  then, 
at  least,  not  more  than  a  trace  of  titanium  is  present. 

To  render  the  qualitative  tests  decisive  one  should  proceed 
exactly  as  outlined  in  the  table  as  to  amounts  of  peroxide  and 
sulphate  added.  Under  the  conditions  given  the  tests  are  very 
satisfactory. 

Further,  the  color  of  plain  vanadium  steel  with  hydrogen  per- 
oxide is  different  from  that  obtained  in  like  manner  with  tita- 
nium. Much  vanadium  (0.40  per  cent)  gives  a  strong  brick  red. 
Small  amounts  yield  a  brown.  Titanium  color  with  hydrogen 
peroxide  is  always  a  clear  yellow  unless  vanadium  is  present. 


ANALYSIS  OF  VANADIUM   STEEL  AND   FERRO-VANADIUM      7 

EXPERIMENT  B. 


Reagent. 

Result. 

Mixture  No.  i. 

{500  mg.  plain  steel,  8 

ist,  added  5  c.c.  H^Oz. 

Distinct  yellow. 

mg.  8%  Ferro  Ti,  or 

2d,  added  5  c.c.  sul- 

Do. 

0.13%  Ti. 

phate. 

3d,  added  i  c.c.  more 

Do. 

of  sulphate. 

4th,  added  i  c.c.  more 

Do. 

of  sulphate. 

5th,  added  i  c.c.  more 

Do. 

of  sulphate. 

6th,  added  i  c.c.  more 

Do 

of  sulphate. 

7th,  added  i  c.c.  more 

Do. 

of  sulphate. 

8th,  added  i  c.c.  more 

Yellow  color  less  dis- 

of sulphate. 

tinct. 

gth,  added  i  c.c.  more 

Yellow  color  fainter. 

of  sulphate. 

loth,  added  i  c.c.  more 

Yellow  color  fainter. 

of  sulphate. 

nth,  added  i  c.c.  more 

Yellow  color  all  gone. 

of  sulphate. 

i2th,   added   i   c.c.   of 

Yellow      color      very 

peroxide. 

strong. 

Mixture  No.  2. 

fsoo   mg.    plain    steel, 
4      10  mg.  22.5%  Ferro 
[     V,  or  0.44%  V. 

ist,  added  5  c.c.  H2O2. 
2d,  added  5  c.c.   sul- 
phate. 

Strong  brick  red  color. 
Red  color  nearly  gone. 

3d,  added  i  c.c.  more 

Red  color  all  gone. 

sulphate. 

{4th,  same  as  above  in 

Red  color  all  gone. 

4th  to  1  2th,  No.  i. 

1  2th,  same  as  above  in 

Red  color  all  gone. 

No.  i. 

i3th,  added  i  c.c.  more 

Slight  return  of  brown. 

of  peroxide. 

i4th,  added  i  c.c.  more 

Faint  coffee  color. 

of  peroxide. 

The  quantitative  determination  of  vanadium  and  chromium* 
in  most  varieties  of  vanadium  steel  can  be  made  in  a  compara- 

*  For  very  small  amounts  of  Cr.  — less  than  o.ioo  per  cent  for  example  —  take 
10  to  40  grams  of  the  steel  and  proceed  by  removing  the  bulk  of  the  iron  by 
BaCOs  as  given  on  page  146.  Fuse  the  ash  as  directed  in  the  footnote  on  page 
146;  add  the  solution  of  the  fusion  of  the  ash  to  the  main  Cr;  convert  to  nitrate 
and  finish  for  Cr  as  usual. 


8  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

lively  simple  way.  The  writer  proceeds  as  follows :  Two  grams 
of  steel  are  heated  in  a  mixture  of  30  c.c.  of  i  :  3  sulphuric  acid 
and  20  c.c.  of  water  in  a  600  c.c.  beaker.  When  the  first  action 
is  over,  60  c.c.  of  1.20  nitric  acid  are  used  to  complete  the  solu- 
tion and  oxidize  the  iron.  Boiling  is  continued  two  minutes 
longer  and  then  200  c.c.  of  water  are  introduced.  From  a  small 
pipette  a  solution  of  permanganate  of  potassium  is  delivered,  a 
little  at  a  time,  until  a  slight  precipitate  of  manganese  oxide  is 
obtained  that  does  not  perceptibly  dissolve  after  twenty  min- 
utes boiling.  The  beaker  is  removed  from  the  fire  and,  after 
a  few  moments,  is  placed  in  a  tray  of  water.  Its  contents  are 
filtered  into  a  heavy  suction  flask  through  an  asbestos  filter 
using  a  ij-inch  carbon  filter  tube,  supporting  the  asbestos  on 
a  perforated  porcelain  plate.*  (The  asbestos  is  washed  in  nitro- 
hydrochloric  acid  and  freed  from  chlorine  test  with  distilled 
water  before  it  is  used.)  The  residue  on  the  asbestos  filter  is 
washed  fifteen  times  with  20  c.c.  of  i  :  3  sulphuric  acid  diluted 
with  500  c.c.  of  water. 

The  filtrate  and  washings  are  returned  to  the  600  c.c.  beaker 
together  with  30  c.c.  of  dilute  sulphuric  acid,  additional.  The 
volume  is  now  about  350  c.c.  and  titration  is  begun  with  a 
standard  of  double  sulphate  of  iron  and  ammonia.  The  double 
sulphate  standard  is  dropped  in  from  a  100  c.c.  burette  until 
the  fluid  in  the  beaker  loses  all  brown  tints  and  assumes  a  prac- 
tically colorless  shade,  in  plain  vanadium,  or  in  vanadium  steels 
containing  less  than  i  per  cent  of  chromium.  If  much  chro- 
mium is  present,  i.e.,  from  2  to  6  per  cent,  the  iron  sulphate 
is  added  until  the  chrome  green  no  longer  grows  darker,  and  two 
or  three  c.c.  more  to  insure  an  excess.  There  are  two  reasons 
why  the  sulphate  standard  should  be  added  at  the  start.  In 
the  first  place,  though  no  chromium  may  have  been  added  to 

*  Now  use  an  alundum  porous  thimble  ij\  inches  outside  diameter  and  2 
inches  high,  supported  in  a  glass  filter  tube  if  inches  O.  D.  by  35  inches  high. 
A  piece  of  flat  Gooch  rubber  tubing  of  if-inch  diameter  is  required  to  make  the 
tight  connection  between  the  thimble  and  the  glass  filter  tube.  This  arrange- 
ment does  away  with  the  use  of  an  asbestos  filter  and  requires  very  little  water 
pressure  for  rapid  filtration.  The  apparatus  is  shown  in  the  photo  on  page  247. 


ANALYSIS  OF  VANADIUM   STEEL  AND   FERRO-VANADIUM      9 

the  steel,  there  is  often  a  little  manganic  oxide  held  in  solu- 
tion, or  permanganate,  which  would  reduce  a  portion  of  the 
sulphate  standard.  Again  there  is  never  any  certainty  that 
small  amounts  of  chromium  are  not  present.  The  quantity  of 
sulphate  standard  required  in  the  foregoing  reduction  should 
be  noted  in  case  the  determination  of  chromium  is  part  of  the 
program.  The  permanganate  of  potassium  standard  is  next 
dropped  into  the  solution  and,  as  soon  as  the  pink  color  begins 
to  disappear  slowly,  the  standard  is  added  three  drops  at  a 
time,  until  a  very  faint  pink  color  is  obtained  that  persists  after 
30  seconds  stirring.  Should  even  as  much  as  five  or  six  per  cent 
of  chromium  be  present  a  practiced  eye  can  easily  detect  pink 
reflections  through  the  chrome  green.  These  pink  glints  can 
be  seen  in  the  bottom  of  the  beaker  and,  as  one  looks  down 
through  the  mouth  of  the  latter,  a  rounded  bright  spot  is  seen 
that  takes  on  a  pink  flush  when  the  permanganate  is  in  excess. 
The  solution  is  now  ready  for  the  titration  of  the  vanadium, 
alone:*  0.6  c.c.  of  potassium  ferricyanide  is  poured  into  the 
beaker  with  a  convenient  dropper,  having  an  etched  mark  on 
it  to  indicate  the  0.6  c.c.,  so  that  the  same  quantity  of  the  indi- 
cator is  always  taken. f  The  ferricyanide  imparts  a  brown 
tint  to  the  iron  solution.  The  ferrous  ammonium  sulphate 
standard  is  again  dropped  in,  a  little  at  a  time,  until  one  drop 
produces  a  green  coloration  that  is  free  from  yellow  tints.f  The 
titration  is  continued  to  a  blue.  The  number  of  c.c.  of  double 
sulphate  standard  required  in  this  second  titration  less  the 
number  needed  to  produce  a  similar  shade  in  an  imitation  test, 
made  with  a  steel  that  does  not  contain  vanadium,  gives  the 
amount  of  the  sulphate  standard  required  to  reduce  the  vanadic 
acid  present.  This  remainder  is  multiplied  by  2.54  to  obtain 
the  number  of  milligrams  of  vanadium  in  the  sample.  With 
each  lot  of  analyses,  two  tests  are  made  of  plain  steels  to  which 

*  Read  pages  39  to  42. 

f  5  grams  of  potassium  ferricyanide  dissolved  in  130  c.c.  of  water, 
t  Titrations  are  now  all  carried  to  a  blue;  i.e.,  until  3  drops  of  the  double  sul- 
phate change  the  dark  green  to  a  distinct  blue. 


10  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

have  been  added  known  weights  of  standard  ferro-vanadium 
drillings  or  powder.  If  the  usual  operations  recover  the  vana- 
dium added  all  of  the  tests  made  at  the  time  are  accepted. 
The  amount  of  double  sulphate  standard  required  by  the  blank 
tests  on  non-vanadium  steels  is  deducted  from  all  tests  before 
making  calculations.  This  deduction  for  plain  vanadium  or 
vanadium-chrome  steels  where  the  per  cent  of  chromium  is  not 
much  in  excess  of  three  per  cent,  varies  from  0.4  to  0.9  c.c.  This 
applies  to  a  volume  of  approximately  350  c.c.  An  increased 
volume  produces  an  increased  blank.  A  test,  in  duplicate,  for 
vanadium  by  the  foregoing  manipulations  can  be  carried  through 
in  an  hour  and  a  half  in  the  presence  of  chromium,  nickel,  tung- 
sten or  molybdenum. 

The  presence  of  much  chromium  increases  the  blank  somewhat. 
With  no  chromium  present  the  blank  is  about  0.3  to  0.4  c.c.  and, 
with  chromium  in  the  solution  to  the  extent  of  3  per  cent,  it 
is  0.7  to  0.9  c.c.  With  a  chromium  content  of  4  per  cent  it  is 
i.o  to  1.2  c.c.  It  is  always  best  to  make  control  tests  and 
blank  tests,  when  high  chromium  and  tungsten  steels  are  being 
analyzed,  with  mixtures  imitating  closely  the  samples  sub- 
mitted for  analysis.  It  is  very  important  when  dealing  with 
alloy  steels,  containing  large  percentages  of  chromium  and 
tungsten,  to  digest  the  drillings  until  the  tungstic  acid 'is  a 
bright  yellow  before  boiling  with  the  excess  of  permanganate 
solution.  One  should,  when  the  tungsten  has  "  cleaned  well," 
add  permanganate  until,  after  20  minutes  boiling,  sufficient 
excess  of  manganese  oxide  is  present  to  give  the  separated 
tungstic  acid  a  chocolate  color.  Then  proceed  as  usual. 

When  nickel  is  present  in  the  steel  in  quantities  ranging  from 
3  to  5  per  cent  the  same  method  applies,  but  it  must  be  borne 
in  mind  that,  when  ferricyanide  of  this  concentration  (5  grams 
in  130  c.c.  of  water)  is  used,  in  a  few  minutes,  nickel  ferricya- 
nide separates,  hence  the  titration  must  be  proceeded  with 
immediately. 

Molybdenum  does  not  interfere  with  the  titration  of  vana- 
dium, though  the  former  element  be  present  in  large  quantities. 


ANALYSIS   OF  VANADIUM   STEEL  AND    FERRO-VANADIUM      II 

*  The  determination  of  vanadium  in  ferro-vanadiums  of 
the  low  silicon  type  offers  no  difficulties  except  that  segregation 
is  considerable.  It  is  always  advisable  to  make  at  least  three 
tests  of  each  sample  and  average  the  results.  From  0.3  to  0.6 
gram  are  taken  and  proceeded  with  exactly  as  in  steels  until 
the  titration  is  to  be  made  when,  instead  of  adding  the 
double  sulphate  standard  first,  the  completeness  of  the  oxida- 
tion of  the  ferro-vanadium  is  tested  by  adding  three  drops  of 
the  permanganate  standard.  If  this  gives  a  suggestion  of  pink 
to  the  solution,  the  ferricyanide  indicator  is  added  and  then  the 
ferrous  sulphate  standard  until  the  light  sky  blue  of  the  vanadyl 
salt  is  darkened  slightly  by  the  deeper  blue  caused  by  the  excess 
of  ferrous  standard.  This  end  point  is  very  satisfactory  but 
requires  a  little  experience  on  the  part  of  the  analyst.  The 
amount  of  sulphate  standard  used  is  noted  and  then  the  per- 
manganate standard  is  added,  at  once,  until  a  distinct  reddish 
pink  color  is  obtained  that  does  not  fade  perceptibly  after  thirty 
seconds  vigorous  stirring.  This  end  point  might  be  described 
as  an  old  rose  shade.  Blanks  are  run  on  the  same  weights  of 
a  plain  carbon  steel  in  exactly  the  same  way  and  deducted  from 
the  amount  of  sulphate  required  to  produce  the  blue  and  from 
the  amount  of  permanganate  required  to  restore  a  pink  color. 
If  less  permanganate  than  sulphate  is  used,  after  correcting 
the  sulphate  reading  to  the  permanganate  basis,  the  presence 
of  chromium  is  indicated  and  a  qualitative  test  for  the  latter 
element  can  be  made  in  an  hour  by  fusing  0.8  gram  of  the  ferro- 
vanadium  with  10  grams  of  sodium  carbonate  mixed  with  2 
grams  of  nitrate  of  potassium.  The  melt  is  dissolved  in  water. 
The  residue  is  removed  by  filtration  in  the  cold.  A  yellow 
tinted  filtrate  confirms  the  presence  of  chromium.  Several 
tenths  of  i  per  cent  of  chromium  are  frequently  present. 

The  amount  of  double  sulphate  should  not  be  taken  as  a 
basis  of  percentage  calculations  unless  it  is  positively  known 
that  chromium  is  absent.  The  sulphate  should  be  first  added 
as  described.  This  should  be  immediately  followed  by  the 

*  Read  pages  35  to  37. 


12  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

addition  of  the  permanganate  standard  as  given  and  the  amount 
of  the  latter  standard  required  to  produce  the  permanent  red- 
dish pink  should  be  multiplied  by  25.4  to  find  the  milligrams 
of  vanadium  in  solution.  For  instance  in  50  per  cent  ferro- 
vanadium  it  is  not  practical  to  take  more  than  0.4  gram  for 
analysis.  One  c.c.  of  the  double  sulphate  equals  0.00086  gram 
of  chromium  or  only  0.215  Per  cent  chromium,  but  it  also  equals 
0.635  Per  cent  vanadium,  i.e.,  0.2  per  cent  chromium  would 
raise  the  vanadium  content  0.6  per  cent  if  not  eliminated  by 
calculating  the  vanadium  from  the  permanganate  used  to 
obtain  the  old  rose  tint.  When  ferro-vanadium  contains  much 
silicon,  about  4  per  cent  or  more,  the  borings  or  powder  may 
not  dissolve  completely  in  sulphuric  and  nitric  acids.  The 
following  modification  is  necessary:  Treat  0.3  to  0.6  gram  of 
sample  with  60  c.c.  1.20  nitric  acid  in  a  No.  5  porcelain  evapor- 
ating dish.  When  heat  produces  no  further  action  add  i  c.c. 
or  more  of  hydrofluoric  acid  which  promptly  gives  a  complete 
solution.  60  c.c.  of  i  13  sulphuric  acid  are  poured  into  the 
dish,  the  watch  glass  is  removed  and  the  solution  is  evaporated 
to  heavy  fumes  to  remove  the  hydrofluoric  acid.  The  sul- 
phates are  dissolved  in  water  and  transferred  to  a  600  c.c.  beaker 
and  the  analysis  completed  as  in  low  silicon  ferro-vanadium. 

Ferro- vanadiums  containing  from  0.5  to  6.0  per  cent  of  copper 
present  a  slight  obstacle.  When  the  ferricyanide  indicator  is 
added  copper  quickly  produces  a  light  yellow  cloud  of  copper 
ferricyanide  that  entirely  prevents  any  end  point  being  seen. 
In  such  cases  a  trial  analysis  is  run  and  a  trial  amount  of  the 
indicator  is  added  just  before  filtering  off  the  excess  of  man- 
ganese. The  copper  is  thus  filtered  out  with  the  manganese. 
The  filtrate  is  proceeded  with  as  usual  and,  if  no  further  clouding 
results  on  adding  0.6  c.c.  more  of  the  ferricyanide  indicator, 
the  titration  is  completed.  Should  more  clouding  occur  the 
analysis  is  repeated  and  twice  as  much  indicator  is  added  before 
filtering  off  the  manganese  oxide.  More  indicator  is  added  to 
the  filtrate  and  the  analysis  completed  in  the  regular  manner. 
Copper  can  be  separated  readily  with  hydrogen  sulphide  or  by 


ANALYSIS   OF  VANADIUM   STEEL  AND   FERRO-VANADIUM     13 

means  of  potassium  sulphocyanate  and  sulphurous  acid,  but 
more  time  is  required  and  nothing  gained.  None  of  the  fore- 
going tests  need  consume  more  than  two  hours  except  when  much 
silicon  is  present  and  resort  to  hydrofluoric  acid  is  necessary. 

As  ferro- vanadium  samples  are,  at  times,  quite  variable  it 
is  always  best  to  make  several  tests  of  the  latter  and  report 
an  average  of  the  results  obtained.  If  the  copper  content  does 
not  exceed  0.3  to  0.4  per  cent,  even  when  two  grams  of  sample 
are  taken,  the  vanadium  can  be  titrated  before  the  clouding 
begins  if  it  is  proceeded  with  as  quickly  as  possible  after  the 
addition  of  the  ferricyanide. 

Small  Amounts  of  Vanadium.  For  the  determination  of 
small  amounts  of  vanadium,  ranging  from  0.02  to  0.05  per 
cent,  it  is  expedient  to  dissolve  from  6  to  8  grams*  of  the  steel 
for  analysis.  Such  large  weights  of  steel  are  treated  first  with 
60  c.c.  of  i  :  3  sulphuric  acid  and  100  c.c.  of  water.  When  this 
action  is  over,  120  c.c.  of  1.20  nitric  acid  are  added  to  complete 
the  solution  and  to  oxidize  the  iron.  Then  continue  the  analy- 
sis as  usual.  Blanks  should  be  carried  along  with  equally 
large  amounts  of  a  plain  carbon  non-vanadium  steel.  The 
writer  would  advise  against  the  addition  of  manganese  sul- 
phate to  discharge  any  persistent  pink  color  when -boiling  with 
permanganate  as  its  use,  in  the  method  as  given,  seems  to 
increase  blanks,  apparently  causing  part  of  the  permanganate  to 
pass  into  solution  in  the  manganic  condition.  Even  the  blank  fil- 
trates have  a  brown  tint  as  though  containing  a  few  hundred ths  of 
one  per  cent  of  chromium.  This  would  seem,  in  a  measure,  sim- 
ilar to  the  solution  of  iron  hydrate  in  iron  salts.  On  discontin- 
uing the  use  of  the  manganese  sulphate,  lower  and  more  uniform 
blanks  and  freedom  from  brown  tints,  therein,  were  attained. 

If  pink  colorations  occur  due  to  excessive  additions  of  the 
permanganate,  dilute  further  with  distilled  water  and  a  drop 

*  As  much  as  40  grams  of  steel  can  be  dissolved,  and  the  bulk  of  the  iron 
removed  with  BaCO3  as  for  Al  as  given  on  page  146.  Fuse  the  ash  as  directed; 
add  the  solution  of  the  fusion  to  the  main  filtrate;  convert  to  nitrates  and  finish 
as  above  for  V. 


14  CHEMICAL  ANALYSIS  OF   SPECIAL  STEELS 

or  two  of  ferrous  sulphate  and  boil  until  they  are  destroyed.  It 
is  rare  that  distilled  water  does  not  contain  enough  traces  of 
organic  matter  to  accomplish  this  purpose.  A  pink  color  in  the 
analysis  of  ferro-vanadium  does  no  harm  in  the  determination 
of  vanadium  as  the  sulphate  standard  is  added  at  the  start;  and 
the  vanadium  is  calculated  from  the  amount  of  permanganate 
required  to  produce  an  old  rose  shade,  after  getting  the  blue 
with  the  sulphate  standard  and  ferricyanide  indicator. 

CARBON. 

The  high  carbon,  low  silicon  ferro-vanadiums  decarbonize 
readily  in  the  electric  furnace  with  oxygen  only.  The  lower 
carbon  grades  and  high  silicon  varieties  yield  better  if  they  are 
mixed  with  an  equal  weight  of  red  lead,  if  burned  in  the  electric 
furnace,  or  with  four  times  their  weight  of  red  lead  in  the  ten- 
burner  Bunsen  combustion  furnace. 

NICKEL. 

Large  amounts  of  vanadyl  salts  in  solution  yield  ammoniacal 
citrates  of  a  very  dark  green  color,  making  it  an  impossibility 
to  see  end  points  in  a  cyanide  and  silver  titration.  The  vanadic 
salts  are  free  from  this  objection:  Dissolve  one  gram  of  the 
ferro-vanadium  in  a  mixture  of  30  c.c.  of  i  :  3  sulphuric  acid 
and  the  same  quantity  of  1.20  nitric  acid.  Use  a  little  hydro- 
fluoric acid  and  then  evaporate  to  fumes  with  sulphuric  acid, 
as  already  described  in  this  chapter,  if  there  should  be  an  insol- 
uble residue  after  heating  with  the  mixed  acids  first  mentioned. 
Boil  the  sulphuric  and  nitric  solution,  or  the  water  solution  of 
the  fumed  residue,  with  an  excess  of  permanganate;  filter  out 
the  oxide  of  manganese;  wash  it  with  sulphuric  acid  water. 
Neutralize  the  free  acid  in  the  filtrate  with  ammonia  before 
adding  the  citric  acid  *  or  the  latter  will  reduce  the  vanadic  to 
hypovanadic  acid  again.  Then  add  a  slight  excess  of  ammonia 
to  the  clear  solution  and  titrate  the  nickel  in  the  regular  way 

*  It  is  still  better  to  add  ammonium  citrate  made  by  neutralizing  the  citric 
acid  with  ammonia.  This  does  away,  entirely,  with  the  vanadium  green. 


ANALYSIS   OF  VANADIUM   STEEL  AND  FERRO-VANADIUM     15 

with  cyanide  and  silver  nitrate.  (See  Chapter  IX.)  If  copper 
is  present  it  will  interfere  and  the  method  given  in  Chapter 
VIII,  part  2,  is  the  simplest  way  to  prevent  the  interference 
due  to  copper,  and,  also,  affords  an  expeditious  plan  to  obtain 
the  percentage  of  the  latter  element  in  the  same  analysis. 

MANGANESE. 

The  manganese  is  obtained  as  in  steels,  by  dissolving  0.050 
to  o.ioo  gram  of  sample  in  40  c.c.  1.20  nitric  acid,  boiling  off 
red  fumes,  further  boiling  for  four  minutes  with  lead  peroxide 
of  a  light  brown  color.  Very  dark  brown  to  black  looking 
lead  peroxide  should  be  rejected,  as  the  black  looking  variety 
invariably  gives  low  results.  In  the  writer's  experience  with  dif- 
ferent lots,  the  black-brown  peroxide  gives  results  from  ten  to 
twenty  per  cent  too  low.  After  boiling  four  minutes  with  the 
brown  peroxide  the  solution  is  promptly  put  into  cool  water  and 
from  there  into  cold  water.  After  the  excess  of  lead  peroxide  has 
been  allowed  to  settle  for  ten  minutes,  or  more,  if  convenient,  the 
pink  solution  is  carefully  decanted  into  a  5  ounce  beaker  and 
titrated  with  a  standard  solution  of  sodium  arsenite  until  the  pink 
shade  is  gone  and  the  slight  yellow  of  the  nitrate  of  iron  appears. 

Chromium  gives  high  results  by  the  process  just  described 
and  must  first  be  removed  as  follows:  Dissolve  0.150  or  0.30 
gram  of  the  chrome  or  chrome-vanadium  steel  in  5  c.c.  of  i  :  3 
sulphuric  acid  in  a  250  by  25  mm.  test  tube,  warming  gently 
till  action  is  over.  Warm  further  with  10  c.c.  of  1.20  nitric 
acid  and  boil  off  red  fumes.  Cool  to  room  temperature;  dilute 
to  about  30  c.c.  with  water.  Add  a  rather  thick  cream  of  zinc 
oxide  until  the  ferric  and  chromic  hydrates  begin  to  settle, 
leaving  a  ring  of  clear  fluid  on  the  top.  Cool  again  and  dilute 
to  the  75  c.c.  mark.  Close  the  tube  with  a  clean  rubber  stopper 
and  mix  the  contents  of  the  test  thoroughly  by  repeated  inver- 
sions of  the  tube.  After  the  precipitate  has  settled  somewhat, 
filter  through  a  dry  filter  into  a  dry  beaker.  Rinse  a  25  c.c. 
pipette  3  times  with  some  of  the  filtrate  and  then  deliver  25  c.c. 
into  a  250  by  25  mm.  test  tube,  add  15  c.c.  of  concentrated 


16  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

nitric  acid,  bring  to  boil,  add  lead  peroxide,  boil  four  minutes 
and  finish  as  in  plain  steels.  This  process  can  be  carried  through 
in  forty-five  minutes  and  is  entirely  accurate  for  technical 
analysis  to  two  per  cent  of  manganese.  The  author  has  en- 
countered ferro-vanadium  with  as  much  as  5  per  cent  of  man- 
ganese together  with  high  silicon.  In  such  cases  a  gram  of 
the  substance  is  fused  exactly  as  though  aluminum  were  being 
sought  for.  The  water  solution  'of  the  melt  is  warmed  with 
alcohol  (a  few  drops)  until  all  green  colorations  are  discharged. 
The  insoluble  residue  is  filtered  out;  washed  with  sodium  car- 
bonate water;  dissolved  off  the  filter  with  hot  i  :  i  hydro- 
chloric acid;  evaporated  to  thick  fumes  of  sulphuric  acid  in  a 
porcelain  dish.  The  residue  is  dissolved  with  water,  trans- 
ferred to  a  liter  flask,  diluted  to  500  c.c,  precipitated  with 
zinc  oxide;  diluted  to  one  liter  and  finished  as  in  high  man- 
ganese in  ferro-titanium.*  (See  page  48.) 

HIGH  SILICON  AND  Low  MANGANESE  FERRO-VANADIUM. 

Such  ferros  cannot  be  analyzed  for  manganese  as  in  steels  on 
account  of  partial  insolubility  in  nitric  acid.  Dissolve  o.ioo 
gram  of  the  alloy  in  a  small  porcelain  dish  or  crucible,  as  far 
as  possible,  with  10  c.c.  1.20  nitric  acid.  When  action  is  over 
add  hydrofluoric  acid  drop  by  drop  until,  with  a  little  further 
heating  it  dissolves  all  to  a  clear  solution  and  no  gritty  or  metallic 
particles  remain.  Add  20  c.c.  i  13  sulphuric  acid  and  evaporate 
to  thick  fumes.  Cool  and  dissolve  the  sulphates  in  10  c.c.,  or 
more,  if  necessary,  of  water,  heating  until  clear  solution  is 
attained.  Wash  into  a  10  by  i  inch  test  tube.  Dilute  to  20  c.c. 
with  water.  Add  10  c.c.  of  cone,  nitric  acid.  Boil  with  brown 
lead  peroxide  and  finish  as  in  steels.  High  silicon  ferro-vana- 
dium with  manganese  above  2  per  cent  could  be  assayed  by 
taking  i.o  gram  of  sample.  Heat  with  30  c.c.  1.20  nitric  acid. 
Clear  all  insoluble  matter  with  hydrofluoric  acid.  Add  60  c.c.  i  13 

*  Or  finish  by  the  author's  method  given  on  page  278  for  manganese  above 
2  per  cent. 


ANALYSIS  OF  VANADIUM   STEEL  AND  FERRO-VANADIUM      17 

sulphuric  acid.  Evaporate  to  thick  fumes.  Dissolve  in  water. 
Transfer  to  a  liter  flask.  Dilute  to  about  500  c.c.  with  water. 
Add  a  slight  excess  of  zinc  oxide.  Dilute  to  the  liter  mark. 
Mix  thoroughly  and  finish  as  given  for  high  manganese  in  ferro- 
titanium.  (Page  48.) 

SULPHUR. 

Ferro-vanadium  does  not  dissolve  completely  in  dilute  hydro- 
chloric acid  so  that  even  approximate  sulphur  tests  by  evolu- 
tion are  not  available.  To  determine  sulphur  in  low  silicon 
ferro-vanadium  dissolve  three  grams  of  sample  in  one  hundred 
c.c.  of  concentrated  nitric  acid  in  a  600  c.c.  beaker.  When 
action  ceases  add  immediately  50  c.c.  of  concentrated  hydro- 
chloric acid  for,  in  alloys  containing  thirty-five  and  higher  per- 
centages of  vanadium,  a  red  precipitate  settles  out  in  large 
quantities  if  hydrochloric  acid  is  not  present  to  dissolve  it.  The 
presence  of  the  red  precipitate  has  a  disadvantage.  It  causes 
the  contents  of  the  different  beakers  to  spurt.  Two  grams 
of  carbonate  of  soda  are  added.  The  solutions  are  transferred 
to  No.  6  porcelain  dishes  and  evaporated  to  dryness.  The 
residue  is  dissolved  in  100  c.c.  of  hydrochloric  acid  and  evapo- 
rated again  to  dryness.  Solution  is  once  more  effected  with 
50  c.c.  of  cone,  hydrochloric  acid  followed  by  evaporation  to  a 
scum.  Ten  c.c.  of  concentrated  hydrochloric  acid  are  employed 
to  dissolve  the  scum;  100  c.c.  of  water  are  added;  the  solution 
is  filtered;  diluted  to  300  c.c.  and  the  sulphate  precipitated 
with  barium  chloride,  using  60  c.c.  of  a  saturated  solution 
diluted  with  240  c.c.  of  water.  Blank  determinations  are 
made  of  exactly  the  same  reagents  and  the  sulphur  found  is 
deducted.* 

One  gram  of  highly  silicious  ferro-vanadium  is  fused  with 
a  mixture  of  20  grams  of  sodium  carbonate  and  four  grams  of 
potassium  nitrate.  The  fusion  is  dissolved  in  water,  acidu- 
lated with  hydrochloric  acid,  evaporated  twice  to  dryness, 


*  Or  fuse  i  gram  with  8  grams  of  Na2O2  in  an  iron  crucible;   dissolve  in  water; 
acidulate  with  HC1,  etc. 


1 8  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

taken  up  with  20  c.c.  of  concentrated  hydrochloric  acid  and 
sufficient  water  to  dissolve  the  sodium  chloride,  and  filtered. 
The  sulphate  in  the  nitrate  is  precipitated  with  barium  chloride 
solution. 

ALUMINUM. 

Aluminum  cannot  be  separated  from  vanadic  solutions  by 
ammonia.  The  latter  are  not  precipitated  by  ammonia  alone, 
but  if  iron  or  aluminum  be  precipitated  in  the  presence  of  vanadic 
or  vanadyl  salts,  large  quantities  of  the  element  are  carried  out 
of  solution  by  the  iron  or  aluminum  in  a  manner  analogous  to 
the  precipitation  of  phosphoric  acid  by  means  of  ferric  salts  and 
ammonia. 

The  following  procedure  gives  a  highly  satisfactory  separa- 
tion. Fuse  0.815  gram  of  ferro-vanadium  in  a  mixture  of  10 
grams  of  sodium  carbonate  and  two  grams  of  potassium  nitrate. 
Raise  the  heat  very  gradually.  Keep  molten  for  a  half  hour. 
Dissolve  the  melt  in  water;  mix  with  filter-paper  pulp;  filter; 
wash  with  water  containing  a  little  sodium  carbonate.  Re- 
turn the  washed  residue  to  the  crucible  in  which  the  fusion 
was  made;  roast;  and  fuse  it  again  with  the  same  mixture.* 
Dissolve  the  fusion  in  hot  water,  preferably  in  a  platinum  dish; 
cool;  add  paper  pulp  made  from  ashless  filter  paper;  filter 
and  wash  as  before.  Combine  the  two  filtrates,  heat  same 
almost  to  boiling,  volume  being  about  600  c.c.;  remove  from 
flame;  add  from  a  burette  i  :  i  hydrochloric  acid,  i.e.,  1.093 
specific  gravity  at  29°  C.  Hold  the  cover  on  the  beaker  in 
an  inclined  position  to  permit  of  stirring  without  loss  of 
spray.  Continue  the  addition  of  the  acid  until  aluminum 
hydroxide  begins  to  cloud  the  solution.  This  will  occur  when 
about  45  c.c.  of  acid  have  been  dropped  in.  Now  add  the 
acid  \  c.c.  at  a  time,  stirring  thoroughly,  until  turmeric  paper 
is  no  longer  turned,  quickly,  to  even  a  faint  brown  by  the  solu- 

*  When  large  amounts  of  Al  and  Fe  are  present,  a  third  or  even  a  fourth  fusion 
is  necessary.     In  such  instances  the  second  method  is  preferable.     (Page  23.) 


ANALYSIS  OF  VANADIUM   STEEL  AND  FERRO-VANADIUM     19 

tion.  The  solution  will  still  be  somewhat  alkaline,  but  it  is 
essential  to  a  good  separation  that  it  be  so,  Very  small  amounts 
of  aluminum  hydroxide  settle  slowly,  requiring  several  hours 
to  collect,  and  giving,  at  first,  only  a  faint  cloudiness  in  the 
solution.  Mix  with  the  precipitate  a  quantity  of  paper  pulp 
about  equal  to  the  volume  the  precipitate  would  occupy  if 
it  were  drained  on  a  filter.  A  wad  about  i  inch  in  diameter 
is  sufficient  in  most  cases.  Wash  with  ammonium  nitrate 
water  (i  gram  of  the  salt  dissolved  in  100  c.c.  of  water).  If  the 
mixture  of  pulp  and  aluminum  hydroxide,  after  being  washed 
15  or  20  times,  is  not  entirely  free  of  yellow  tint,  it  should 
be  dried;  the  paper  burned  off  in  the  platinum  crucible  and 
the  residue  fused  once  more  with  Na2COs,  only,  and  treated 
exactly  as  before,  i.e.,  dissolved  in  water  and  precipitated  with 
i  :  i  hydrochloric  acid.  This  insures  a  snow  white  pre- 
cipitate, free  of  vanadium.  The  aluminum  hydroxide  being 
now  free  of  vanadium  is  dissolved  off  the  filter  with  50  c.c. 
of  hot  i  :  i  hydrochloric  acid.  The  hot  acid  is  poured  on 
the  pulp  six  times,  reheating  the  solvent  at  each  pouring. 
The  paper  pulp  is  washed  free  from  chlorides  with  water. 
The  filtrate  and  washings  are  heated  to  boiling,  and  the 
aluminum  hydroxide  is  precipitated  in  the  usual  way  with 
a  slight  excess  of  ammonia,  paper  pulp  added  and  the  hy- 
droxide washed,  roasted  and  blasted  to  a  constant  weight 
as  A12O3+  P2O5  +  Si02. 

Test  all  of  the  filtrates  mentioned  in  the  foregoing  outline 
by  adding  an  excess  of  acid  and  then  a  slight  excess  of  ammonia 
to  make  certain  that  the  various  manipulations  have  been 
properly  conducted. 

The  writer  has  repeatedly  observed  in  making  the  separation 
of  much  aluminum  from  much,  or  indeed  any,  vanadium  that 
if  the  neutralization  of  the  hot  sodium  carbonate  fusion  be 
carried  farther  than  here  given  the  aluminum  hydroxide  will 
contain  vanadium.  In  short,  make  sure  that  the  solution 
is  still  distinctly  alkaline.  To  guard  against  presence  of  silica 
it  is  well  to  add  10  c.c.  of  hydrofluoric  acid  and  a  few  drops  of 


20  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

sulphuric  acid  to  the  A12O3  +  ?2O5  +  SiO2.     Evaporate;    ig- 
nite;  and  weigh  again.* 

The  phosphorus  in  the  precipitate  is  estimated  and  deducted  as 
follows:  Fuse  the  precipitate  with  10  grams  of  sodium  carbon- 
ate; dissolve  in  water;  precipitate  with  i  :  i  HC1  as  described; 
dissolve  off  the  filter  with  50  c.c.  of  hot  i  :  i  hydrochloric  acid 
and  wash  free  of  chlorides  as  usual.  Evaporate  to  5  c.c.;  add 
100  c.c.  of  concentrated  nitric  acid;  evaporate  again  to  10  c.c. 
Dilute  with  20  c.c.  of  water;  filter  through  a  small  filter  and 
wash  with  very  dilute  nitric  acid.  Evaporate  the  filtrate  and 
washings  to  50  c.c.;  boil  with  a  slight  excess  of  permanganate 
of  potash ;  clear  with  a  small  excess  of  ferrous  sulphate  followed 
by  an  addition  to  the  still  hot  solution  of  50  c.c.  of  molybdate 
solution.  Finish  as  in  phosphorus  in  steels;  calculate  to  P205 
and  deduct  from  the  weight  of  silica  free  A1203  +  P206.  The 
remainder  is  the  pure  A^Oa.  The  acid  precipitation  of  alumi- 
num hydroxide  is  an  application  of  the  well-known  reaction, 
Al  (ONa)3  +  3  HC1  =  3  NaCl  +  Al  (OH)  3.  Treadwell  mentions 
that  W.  F.  Hillebrand  recommends  this  separation  of  aluminum 
from  small  amounts  of  vanadium  found  in  ores  of  iron  and  in 
rocks.  The  writer  has  never  had  the  pleasure  of  reading  Hille- 
brand's  article.  The  reference  is  given  as  American  Journal  of 
Science  (4),  VI,  p.  209. 

PHOSPHORUS. 

Vanadium  precipitates  with  the  phosphorus  if  an  attempt 
be  made  to  determine  the  percentage  of  the  latter  element 
by  a  molybdate  separation  as  ordinarily  practiced  in  steel 
analysis.  The  phospho-molybdate  is  colored  by  presence  of 
vanadium,  being  of  a  rather  dark  orange  color.  Further, 
in  the  presence  of  much  vanadium  most  of  the  phosphoric 
acid  is  not  precipitated  by  the  molybdate  solution  as  used 
in  steels. 

*  Blanks  must  be  made  including  all  fusions,  acidulations,  evaporations  and 
every  other  step  in  the  foregoing  scheme  as  the  chemicals  are  almost  certain  to 
be  impure;  and  glassware  and  dishes  are  more  or  less  attacked. 


ANALYSIS  OF   VANADIUM   STEEL  AND   FERRO-VANADIUM     21 

Having  noted  vagaries  that  have  been  commented  on  by 
several  authors  of  works  on  the  analysis  of  iron  and  steel,  and 
not  having  read  any  suggestion  that  improved  the  situation, 
some  experiments  were  made  to  study  the  matter.  First  the 
boiling  of  the  nitric  acid  solution  of  the  alloy  with  a  very  slight 
excess  of  potassium  permanganate  and  then  clearing  with  just 
one  drop  of  ferrous  sulphate  was  tried,  that  is,  a  precipitation 
in  the  presence  of  vanadic  acid.  Second,  as  before,  except 
that  a  large  excess  of  ferrous  sulphate  was  added  after  boiling 
with  permanganate,  being  a  precipitation  in  the  presence  of 
vanadyl  salt.  These  two  conditions  were  further  modified  by 
varying  the  length  of  time  between  the  addition  of  the  molyb- 
date  solution  and  the  subsequent  filtering  out  of  the  yellow  or, 
rather,  red  precipitate.  The  discordant  results  are  given  in 
Table  i,  together  with  the  actual  phosphorus  as  obtained  by 
the  writer's  aluminate  method  (page  22). 

From  such  results,  and  others  not  given,  it  was  decided  to 
remove  the  vanadium  entirely  from  the  phosphorus  and  then 
precipitate  with  molybdate.  As  iron  carries  large  quantities  of 
vanadium  with  it  when  precipitated  in  the  presence  of  the  former 
element  by  ammonia,  phosphorus  could  not  be  separated  as  ferric 
phosphate.  A  number  of  other  schemes  were  resorted  to,  and 
finally  the  following  plan  proved  successful,  and  demonstrated, 
as  given  in  the  table,  that  as  little  as  one-fourth  of  the  phos- 
phorus is,  at  times,  obtained  by  the  ordinary  methods  as  given  in 
the  most  recent  books  on  the  analysis  of  steel  works  materials. 

A  solution  of  sodium  aluminate  was  prepared  by  placing 
10  grams  of  metallic  aluminum  in  a  large  dish  (platinum  pre- 
ferred) together  with  50  grams  of  stick  caustic  soda.  Water 
was  added  a  drop  at  a  time  as  the  action  proved  extremely 
violent,  much  heat  being  generated.  When  the  reaction  was 
complete  the  mass  of  aluminate  was  dissolved  in  water;  some 
paper  pulp  was  added;  the  solution  was  filtered,  and  the  filtrate 
and  washings  were  diluted  to  520  c.c. 

A  double  fusion  using  10  grams  of  sodium  carbonate  and 
2  grams  of  potassium  nitrate,  each  time,  is  made  of  0.815  gram 


22 


CHEMICAL  ANALYSIS   OF  SPECIAL  STEELS 


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ANALYSIS  OF   VANADIUM   STEEL  AND   FERRO-VANADIUM     23 

of  the  powdered  sample  in  exactly  the  same  manner  as  just 
described  for  the  aluminum  separation.  Add  to  the  combined 
nitrates  and  washings  from  the  iron  residue  5  c.c.  of  the  sodium 
aluminate  solution  and  precipitate  it  with  i  :  i  hydrochloric 
acid,  adding  the  acid  until  the  solution  no  longer  changes  tur- 
meric paper,  at  once,  to  even  a  faint  brown. 

The  precipitated  aluminum  hydroxide  and  phosphate  are 
washed  15  times  with  ammonium  nitrate  solution,  roasted  in 
a  platinum  crucible,  and  fused  again  with  10  grams  of  Na2C03+ 
2  grams  KNOa.  The  melt  is  dissolved  in  water,  and  precipitated 
again  with  i  :  i  hydrochloric  acid  as  described  under  aluminum. 
This  precipitate  is  then  washed,  converted  into  nitrate,  and 
the  phosphorus  is  separated  with  molybdate  solution.  It  is 
a  bright  yellow,  totally  free  of  red  tint.  The  extent  to  which 
vanadium  holds  phosphorus  in  solution  is  shown  by  the  results 
obtained,  which  are  also  given  in  the  table  for  convenient  com- 
parison. The  United  States  Bureau  of  Standards  pig  iron 
"B"  was  dissolved  in  1.20  nitric  acid,  evaporated,  ignited  to 
a  dull  red,  dissolved  in  hydrochloric  acid,  precipitated  with 
ammonia;  washed;  roasted  in  a  platinum  crucible  and  treated 
as  though  it  were  a  ferro- vanadium.  The  phosphorus  was 
obtained  by  the  aluminate  and  acid  scheme.  A  laboratory 
standard  was  tested  in  like  manner  for  phosphorus.  The  cor- 
rect phosphorus  was  obtained  in  each  sample. 

SECOND  METHOD  FOR  ALUMINUM  AND  PHOSPHORUS  IN 
FERRO-VANADIUM. 

Dissolve  one  gram  of  sample  in  40  c.c.  1.20  nitric  acid.  If 
there  remains  an  insoluble  metallic  residue  when  the  percentage 
of  silicon  is  high,  filter  out  the  undissolved  part.  Wash  it 
with  1.20  nitric  acid.  Roast  off  the  paper  pulp.  Fuse  it  with 
twenty  times  its  weight  of  Na2CO3  plus  one-fifth  its  weight  of 
potassium  nitrate.  Dissolve  the  melt  with  water  in  a  plati- 
num dish.  Transfer  the  water  solution  to  a  porcelain  dish;  add 
an  excess  of  i  :  i  hydrochloric  acid.  Heat  until  all  is  dissolved. 
Clean  the  crucible  with  i  :  i  hydrochloric  acid  when  all  is  in  solu- 


24  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

tion.  Transfer  the  acidulated  fusion  and  the  cleanings  of  the 
crucible  to  a  1000  c.c.  boiling  flask.  Also  add  to  the  same,  the 
nitrate  and  washings  from  the  residue  that  remained  undissolved 
in  nitric  acid.  Dilute  to  about  300  c.c.  Hold  the  flask  in  one 
hand,  and  project  into  it  with  the  other  hand,  from  a  small 
porcelain  spoon,  sodium  peroxide,  a  gram  or  two  at  a  time. 
When  sufficient  peroxide  has  been  added  to  precipitate  all  of 
the  iron,  then  add  an  excess  of  10  grams  of  the  former;  also 
10  grams  of  sodium  carbonate  to  supply  carbon  dioxide.  Boil 
twenty  minutes;  cool  and  filter  out  the  iron  hydroxide,  mixing 
with  it  a  large  amount  of  paper  pulp.  Wash  this  mixture  on 
the  filter  with  sodium  carbonate  water  twenty  times.  The  filter 
should  be  a  double  12  cm.  one.  The  strongly  alkaline  solution 
is  diluted  with  100  c.c.  of  water  before  the  iron  hydroxide  is 
filtered  from  it.  Each  washing  is  well  drained  off  before  the 
next  one  is  added.  A  small  square  of  cheese-cloth  is  folded 
in  with  the  filter  at  the  apex  to  prevent  the  alkaline  solution 
from  tearing  the  paper.  This  filtrate  and  washings  are  desig- 
nated A. 

Dissolve  the  iron  residue  off  the  filter  and  treat  it  with 
peroxide  and  10  grams  of  carbonate  exactly  as  before,  obtain- 
ing filtrate  B. 

PHOSPHORUS. 

(A)  Heat  the  filtrate  and  washings  from  the  iron  hydroxide 
obtained  in  the  first  peroxidation ;  add  5  c.c.  of  the  alumina te 
solution.  Mix  well.  Then  introduce  i  :  i  hydrochloric  acid 
as  described  in  the  first  method  for  phosphorus.  Keep  the 
solution  slightly  but  distinctly  alkaline.  The  acid  is  added 
until  the  solution  no  longer  gives  turmeric  paper  a  faint  brown 
tint,  quickly.  Filter  off  the  aluminum  hydroxide,  mixing  paper 
pulp  with  it.  Dissolve  the  hydroxide  off  the  filter  with  40  c.c. 
of  i  :  i  hydrochloric  acid,  after  first  washing  15  times  with  ammo- 
nium nitrate  water.  Pour  the  hot  acid  back  and  forth  over 
the  pulp  six  times,  heating  the  acid  before  each  pouring.  Wash 
the  pulp  free  from  chloride  test  with  water. 


ANALYSIS  OF  VANADIUM   STEEL  AND  FERRO-VANADIUM     25 

The  filtrate  and  washings  from  the  pulp  are  peroxidized, 
also.  This  time  add  only  enough  peroxide  to  insure  alkalinity 
and  to  dissolve  any  aluminum  hydroxide  that  may  appear. 
Boil  the  solution  10  seconds,  adding  10  grams  of  sodium  car- 
bonate before  boiling.  Remove  from  the  flame  and  precipitate 
as  before  with  i  :  i  HC1.  Filter  off  aluminum  hydroxide  and 
finish  as  given  for  phosphorus  in  the  first  method.  Add  a 
slight  excess  of  acid  to  the  filtrate  and  washings;  then  a  faint 
excess  of  ammonia  to  make  sure  that  all  aluminum  hydroxide 
has  been  precipitated.  The  aluminum  hydroxide  is  put  through 
this  second  peroxidation  to  remove  any  vanadium  that  is  car- 
ried down  with  it  the  first  time  it  is  precipitated  with  acid. 
It  should  now  look  pure  white,  free  from  any  suggestion  of 
yellow  tint.  If  it  has  a  yellow  color,  too  much  acid  has  been 
used  in  its  precipitation.  In  that  event  it  must  be  dissolved 
off  the  filter  and  peroxidized  again,  but  unless  proper  degree 
of  alkalinity  is  observed  it  will  still  appear  yellow. 

(B)  The  filtrate  and  washings  from  the  second  peroxidation 
of  the  iron  are  treated  with  5  c.c.  of  alumina te  solution  and  then 
as  described  for  those  obtained  from  the  first  peroxidation; 
but  as  practically  no  vanadium  is  present  in  the  second  peroxi- 
dation, this  aluminum  hydroxide  is  free  of  any  vanadium  and 
can  be  dissolved  off  the  filter  and  converted  into  nitrate  at 
once  to  obtain  the  remainder  of  the  phosphorus. 

(C)  The  iron  residue  after  its  second  peroxidation  is  dis- 
solved off  its  filter  with  hot  1.20  nitric  acid,  pouring  the  acid 
back  on  the  filter  six  times,  stirring  up  the  pulp  each  time  with 
a  glass  rod.     Wash  40  times.    Evaporate  filtrate  and  washings 
to  40  c.c.     Boil  with  permanganate  and  finish  as  in  steels. 
Only  a  few  thousandths  of  a  per  cent  of  phosphorus  are  found 
with  the  iron,  even  with  a  phosphorus  content  of  0.24  per  cent. 

This  method  avoids  all  fusions  except  one,  and  that  one  is 
necessary  only  in  high  silicon  ferros.  It  checks  perfectly  with 
the  first  method  and  is  really  an  outgrowth  of  it.  However, 
it  requires  more  of  the  operator's  time  in  that  he  cannot  give 
his  attention  to  much  else  while  making  the  peroxidations. 


26  CHEMICAL  ANALYSIS   OF   SPECIAL   STEELS 

It  is  an  economy  of  platinum  rather  than  of  time.*  If,  after 
removing  the  vanadium  by  either  the  first  or  second  methods 
for  phosphorus,  the  phospho-molybdate  still  retains  an  orange 
shade  rather  than  a  light  canary  yellow,  vanadium  is  still  present 
to  some  extent,  and  a  considerable  portion  of  the  phosphorus 
is  surely  held  in  solution.  It  means  that  some  part  of  the  direc- 
tions have  not  been  exactly  followed.  The  trouble  is  almost 
certain  to  be  due  to  having  precipitated  the  aluminum  hydroxide 
in  too  faintly  alkaline  solution.  For  example,  if  the  color  of 
the  phospho-molybdate  suggests  even  a  slight  red  and  the  pre- 
cipitates tend  to  adhere  to  the  bottom  of  the  beaker,  a  result 
of  0.19  per  cent  may  be  obtained  when  the  actual  phosphorus 
is  0.25  per  cent. 

As  the  amount  of  phosphorus  remaining  with  iron  after  the 
first  peroxidation  is  very  trifling  for  all  practical  purposes,  it 
is  not  necessary  for  steel  works,  or  indeed  most  technical  anal- 
ysis, to  make  a  second  peroxidation  of  it.  In  this  way  it  is 
simply  necessary  to  make  the  one  peroxidation  to  remove  iron, 
and  the  total  phosphorus  is  then  separated  from  the  vanadium 
in  the  filtrate  as  given.  However,  should  more  than  0.25  per 
cent  phosphorus  be  found,  it  would  be  safer  to  follow  the  entire 
method  as  first  described. 

Add  o.ioo  gm.  of  aluminum  dissolved  in  hydrochloric  acid 
or  5  c.c.  of  aluminate  solution  for  every  0.25  per  cent  of  phos- 
phorus supposed  to  be  present  in  the  ferro. 

ALUMINUM. 

Proceed  exactly  as  for  phosphorus,  but  add  no  aluminate. 
Any  precipitate  that  forms  with  i  :  i  HC1  is  then  treated  as 
described  in  the  first  method  for  aluminum.  This  process 
avoids  all  fusions  except  the  one  required  when  silicon  is  high. 
A  blank  must  be  run,  imitating  the  test  in  every  detail.  A 
plain  carbon  steel  can  be  used  for  the  blank,  weighing  out  approx- 
imately as  much  of  it  as  there  is  supposed  to  be  iron  present  in 

*  It  can  be  used  to  advantage  when  a  number  of  samples  are  assayed  at  the 
same  time. 


ANALYSIS  OF  VANADIUM  STEEL   AND   FERRO- VANADIUM     27 

the  ferro.  This  separation  of  aluminum  from  vanadium  and 
iron  has  been  tested  by  the  author  with  mixtures  containing 
as  much  as  10  per  cent  of  aluminum  and  50  per  cent  of  vana- 
dium, the  remainder  being  iron,  on  a  one-gram  basis. 

A  good  way  to  run  a  blank  for  either  aluminum  or  phos- 
phorus is  to  dissolve  100  mgs.  of  metallic  aluminum  of  known 
aluminum  content  in  a  few  c.c.  of  hydrochloric  acid.  Add  this 
to  400  mgs.  of  a  plain  carbon  steel.  Put  the  mixture  through 
the  entire  analysis.  Deduct  the  excess  of  aluminum  found 
from  the  aluminum  obtained  from  the  ferro.  The  remainder 
will  be  the  aluminum  sought  in  the  ferro- vanadium.*  Deduct 
the  phosphorus  found  in  this  blank  test  from  that  found  by 
the  same  process  in  the  ferro,  allowing  for  the  phosphorus 
known  to  be  in  0.400  gram  of  steel  used. 

Instead  of  using  the  aluminate  solution  for  the  phosphorus 
determination,  100  mgs.  of  aluminum  can  be  added,  after  dis- 
solving it  in  a  few  c.c.  of  i  :  i  hydrochloric  acid,  whenever  the 
foregoing  directions  call  for  5  c.c.  of  aluminate.  In  this  way 
the  aluminum  and  phosphorus  can  be  gotten  from  the  same 
analysis.  It  is  merely  a  matter  of  deducting  from  the  total 
aluminum  found,  the  aluminum  added,  and  also  the  blank.  Add 
100  mgs.  of  aluminum  dissolved  in  hydrochloric  acid  for  every 
0.25  per  cent  of  phosphorus  when  one  gram  of  sample  is  taken 
for  analysis.  The  phosphorus  is  gotten  last  by  fusing  the 
A1-2O3  +  P2Os  after  it  has  been  weighed  in  the  silica  free  condi- 
tion. Fuse  the  oxides  with  sodium  carbonate,  using  10  grams. 
Dissolve  the  melt  in  water.  Precipitate  the  water  solution  as 
usual  with  i  :  i  hydrochloric  acid.  Filter  off  the  aluminum  hy- 
droxide, etc.  Wash  it  a  few  times.  Mix  paper  pulp  with  the 
hydroxide  to  hasten  nitration  and  washings.  Dissolve  the  hy- 
droxide off  the  filter  with  50  c.c.  i  :  i  hot  hydrochloric  acid  as 
previously  described  in  the  first  method.  Wash  the  pulp  free  of 
chlorides.  Evaporate  the  filtrate  and  washings  to  about  10  c.c. 

*  For  example  if  o.ioo  gm.  of  99.5  per  cent  aluminum  is  added  to  400  mgs. 
of  a  plain  steel  and  o.uo  gm.  is  recovered  by  the  method,  then  the  blank  would 
be  o.uo  —  0.0995  °r  0.0105  gm. 


28  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Add  ioo  c.c.  of  cone,  nitric  acid  and  evaporate  to  15  c.c.  Rinse 
into  a  5  oz.  beaker.  Boil  with  permanganate  solution  and  finish 
as  in  steels. 

As  considerable  silicic  acid  is  obtained  from  the  operations 
in  this  second  method,  it  is  better  to  remove  the  silicon  by 
evaporating  the  aluminum  chloride,  etc.,  to  dryness  just  before 
precipitating  it  to  weigh  it  as  A^Os  -f-  P20s.  This  avoids  the 
use  of  hydrofluoric  acid. 

A  single  peroxidation  is  not  sufficient  to  separate  the  alu- 
minum from  the  iron.  A  little  is  always  found  in  the  filtrate 
from  the  iron  hydroxide  after  its  second  peroxidation.* 

IRON. 

The  iron  residue  obtained  from  fusions  for  aluminum  or 
phosphorus  is  roasted  free  of  paper;  dissolved  with  hydro- 
chloric acid.  The  crucible  in  which  the  fusions  were  made  is 
cleaned  by  warming  a  little  of  the  same  acid  in  it.  The  clean- 
ings are  added  to  the  main  solution  of  the  residue.  Sixty  c.c. 
of  i  :  3  sulphuric  acid  are  introduced,  and  the  solution  is  evap- 
orated to  thick  fumes.  The  residue  is  dissolved  in  300  c.c.  of 
water,  and  hydrogen  sulphide  is  passed  through  it  until  the 
various  sulphides  have  settled  out  well.  The  reduced  iron  is 
filtered  free  of  sulphides  into  a  round  flask.  Hydrogen  sul- 
phide is  again  passed  through  the  solution  to  reduce  any  iron 
that  may  have  become  oxidized  during  filtering  and  washing. 
The  hydrogen  sulphide  is  removed  by  boiling  the  solution  with 
carbon  dioxide  passing  rapidly  through  it.  When  the  gases 
coming  from  the  hot  flask  no  longer  cause  filter  paper  mois- 
tened with  lead  acetate  to  turn  brown  or  black,  the  flask  is 
cooled  in  water  with  carbon  dioxide  still  passing.  When  cold 
the  solution  is  titrated  with  a  potassium  permanganate  stand- 
ard, i  c.c.  of  which  equals  0.00556  gram  of  iron,  made  by  dis- 
solving 3.16  grams  of  c.p.  permanganate  in  water  and  diluting 
to  one  liter.  (See  Standardization  of  KMnC>4,  page  49.) 

*  If  the  Al  present  is  found  to  exceed  10  per  cent,  it  is  safer  to  make  a  third 
peroxidation. 


ANALYSIS   OF  VANADIUM   STEEL  AND  FERRO-VANADIUM     29 

The  writer  frequently  uses  the  plan  of  dissolving  the  ferro 
in  sulphuric  and  nitric  acids,  with  a  little  hydrofluoric  acid 
if  necessary.  Evaporation  to  fumes  and  solution  in  water 
are  the  next  steps.  The  vanadium  and  iron  are  then  reduced 
with  hydrogen  sulphide,  the  solution  is  filtered,*  hydrogen  sul- 
phide is  removed  with  C02,  and  permanganate  of  potash  stand- 
ard is  added  until  a  pink  is  obtained  or  an  old  rose  shade,  that 
does  not  fade  perceptibly  after  one  minute's  stirring.  2.5  c.c. 
of  ferricyanide  indicator  are  now  dropped  in,  and  a  ferrous 
ammonium  sulphate  standard,  i  c.c.  of  which  equals  i  c.c.  of 
the  permanganate,  is  added  until  three  drops  of  this  standard 
cause  the  light  blue  of  the  vanadyl  solution  to  darken  with  the. 
blue  of  the  ferricyanide  of  iron.  The  number  of  c.c.  of  perman- 
ganate used  to  produce  the  old  rose  shade  less  the  number  of  c.c. 
of  sulphate  required  equals  the  number  of  c.c.  of  permanganate 
used  to  oxidize  the  iron,  which  number  multiplied  by  0.00556  gives 
the  amount  of  iron  in  parts  of  a  gram.  The  number  of  c.c.  of 
sulphate  used  to  produce  a  darkened  blue,  multiplied  by  0.00508 
(provided  the  sulphate  exactly  equals  the  permanganate),  equals 
the  number  of  grams  or  parts  of  a  gram  of  vanadium  present. 

The  iron  residue  from  the  carbonate  and  niter  fusions  may 
be  proceeded  with  for  the  estimation  of  the  latter  metal  in  this 
way:  After  removing  the  platinum,  copper,  etc.,  from  the 
hydrochloric  acid  solution  of  the  iron  oxide  by  hydrogen  sul- 
phide, evaporate  the  filtrate  and  washings  from  the  sulphides 
with  a  small  excess  of  potassium  chlorate.  Remove  the  hydro- 
chloric acid  by  evaporation  to  thick  fumes  with  60  c.c.  i  :  i 
sulphuric  acid.  Add  water;  dissolve  by  heating;  reduce  with 
metallic  zinc;  and  titrate  with  standard  permanganate  for  iron. 

COPPER. 

If  copper  is  present  to  any  appreciable  extent,  as  shown  by 
the  clouding  with  the  ferricyanide  indicator,  it  can  readily  be 

*  Immediately  after  filtering  out  the  sulphides,  pass  HzS,  again,  for  30  min- 
utes to  reduce  any  iron  that  may  have  become  oxidized  during  the  filtration  and 
washing  of  any  metallic  sulphides  that  may  have  formed.  Then  pass  CO2  to 
remove  the  excess  of  H2S  as  above. 


30  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

separated  by  hydrogen  sulphide,  passing  the  latter  gas  through 
the  sulphate  solution  obtained  by  dissolving  the  sample  in 
nitro-sulphuric  acid,  using  a  little  hydrofluoric  acid  if  much 
silicon  be  present,  evaporating  to  fumes  of  sulphuric  acid  and 
dissolving  in  boiling  water  to  hasten  solution.  Copper  can 
also  be  easily  and  quickly  separated  from  this  sulphate  solu- 
tion by  neutralizing  most  of  the  free  acid  and  precipitating 
the  copper  with  an  excess  of  potassium  thiocyanate  and  sul- 
phurous acid.  (Also  see  the  author's  ferricyanide  separation.) 
The  sulphide  of  copper  is  filtered,  washed  with  hydrogen  sul- 
phide water,  roasted  free  of  paper  in  a  porcelain  crucible,  dis- 
solved in  1.20  nitric  acid,  and  filtered  from  any  insoluble  sulphides 
or  alumina.  The  filtrate  and  washings  are  made  slightly  alkaline 
with  sodium  carbonate  water;  one  c.c.  of  ammonia  is  added 
and  the  solution  titrated  to  disappearance  of  a  blue  with  potas- 
sium cyanide  standardized  against  99.8  per  cent  metallic  copper 
in  the  same  manner. 

Chromium,  as  already  intimated,  when  present,  can  be  deter- 
mined in  the  presence  of  vanadium  and  in  the  same  operation. 

In  steels  the  amount  of  double  sulphate  used  to  discharge 
all  red  colorations,  leaving  the  solution  a  clear  light  green,  free 
of  all  yellowish  tints,  less  the  number  of  c.c.  of  the  perman- 
ganate standard  required  to  produce  a  slight  permanent  pink 
reflection,  thereafter,  equals  the  amount  of  double  sulphate 
necessary  to  reduce  the  chromic  acid  present  to  chromic  sul- 
phate. One  c.c.  of  the  double  sulphate  usually  equals  0.00087 
gram  of  chromium.  As  already  explained,  the  ferricyanide 
indicator  is  now  dropped  in,  and  the  sulphate  standard  again 
follows  until  three  drops  of  it  produce  a  blue.*  The  amount 
of  sulphate  consumed  by  this  last  titration  is  equivalent  to 
the  vanadic  acid  present,  after  deducting  the  regular  blank, 
which  is  usually  0.4  to  i.o  c.c.,  depending  on  the  amount  of 
chromium.  A  sample  calculation  is  given  as  an  illustration. 
(2  grams  are  taken  for  analysis.) 

*  The  sulphate  standard  is  now  added  until  three  drops  of  it  change  the  dark 
green  to  a  blue. 


ANALYSIS   OF   VANADIUM   STEEL  AND   FERRO-VANADIUM     31 

FIRST   PART   OF   THE   TITRATION   TO   OBTAIN   THE    CHROMIUM.        (MADE    BEFORE 
ADDING  FERRICYANIDE.) 

KMnO4  Double  Sulphate. 

9 .  i  c.c.  second  reading  of  burette         28 . 6  c.c. 

2 . 3  c.c  first  reading  of  burette  12.4  c.c. 
6. 8  c.c.  i6.2c.c. 

CALCULATION. 
16.2 

6.8 

9 . 4  c.c.  equal  sulphate  used  by  chromium. 

9.4  X  0.00087  X  100  -T-  2  =  0.4089,  or  per  cent  chromium. 

SECOND   PART  OF   THE  TITRATION    (MADE   IMMEDIATELY  AFTER  ADDING  THE   FERRI- 
CYANIDE INDICATOR)  TO  OBTAIN  THE  VANADIUM. 

Sulphate. 

31 .4  c.c.  second  reading  of  burette. 
28 . 6  c.c.  first  reading  of  burette. 

2.8C.C. 

0.4  c.c.  equals  regular  vanadium  blank  for  low  per  cent  chromium. 
2. 4  c.c. 

Since  i  c.c.  of  sulphate  equals  i  c.c.  of  permanganate  or 
0.00254  gram  of  vanadium,  therefore  2.4  X  0.00254  X  100 
-T-  2  =  0.305  per  cent  vanadium. 

SMALL  AMOUNTS  or  CHROMIUM. 

Ferro-vanadium  frequently,  as  stated,  contains  one  or  two 
tenths  of  a  per  cent  of  chromium.  The  most  satisfactory  way 
to  estimate  these  small  amounts,  in  the  presence  of  large  per 
cents  of  vanadium,  is  to  fuse  i  gram  of  the  finely  ground  powder 
or  thin  drillings  with  20  grams  of  sodium  carbonate  and  4  grams 
of  niter.  After  the  fusion  is  quiet,  keep  it  molten  for  thirty 
minutes.  Dissolve  the  melt  in  as  little  water  as  possible  in  a 
platinum  or  porcelain  dish.  Add  pulp;  filter;  wash  with  sodium 
carbonate  water.  Evaporate  the  nitrate  and  washings  to  about 
40  c.c.  If  the  solution  is  not  clear,  add  a  little  pulp,  filter  and 
wash  again.  The  filtrate  and  washings  should  not  exceed  40  to 
50  c.c.  if  the  chromium  content  is  only  a  tenth  of  a  per  cent  or 
thereabout.  Compare  this  solution  with  a  standard  consisting 
of  0.070  gram  of  c.p.  potassium  dichromate  made  slightly  alkaline 


32  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

with  sodium  carbonate  and  diluted  to  250  c.c.  in  a  volumetric 
flask.  It  is  made  alkaline  by  adding  sodium  carbonate  until  the 
red  color  of  the  dichromate  has  all  been  converted  into  the  yellow 
of  the  sodium  chromate.  i  c.c.  equals  o.oooi  gram  of  chromium. 
Use  the  same  comparison  tubes  as  described  under  the  color 
method  for  titanium.  Rinse  one  of  the  tubes  three  times  with 
some  of  the  standard.  Then  pour  into  it  exactly  10  c.c.  of  the 
standard  solution.  If  the  chromium  content  is  about  0.20  per 
cent,  the  standard  will  be  yellower  than  the  test.  Add  water  to 
the  standard,  i  to  2  c.c.  at  a  time,  until  its  color  is  only  slightly 
stronger  than  that  of  the  test.  Continue  the  addition  of  water  in 
J  c.c.  amounts  until  the  standard  is  just  turned  lighter  than  the 
test.  Suppose  the  standard  matches  the  test  in  color  at  27.5  c.c. 
and  the  volume  of  the  test  is  59.5  c.c.  This  gives  the  proportion: 

Standard  Vol.  Test  Vol.  10  c.c.  Std. 

27.5  :          59.5         :   :        o.ooi       :    X 

5.95  -T-  27.5  =  o. 2 1,  or  o. 2 1  per  cent  chromium. 

MOLYBDENUM. 

*  Molybdenum  is  separated  exactly  as  the  copper  with  hydro- 
gen sulphide  in  slightly  acid  solution.     The  brown  sulphide  is 
roasted  at  a  low  heat  in  a  porcelain  crucible  to  a  white  or  a 
bluish  white  residue   (unless  dark  colored  oxides  are  present, 
such  as  copper).     The  white  oxide  is  brushed  into  a  platinum 
crucible,  fused  with  ten  times  its  weight  of  sodium  carbonate; 
dissolved  in  water;    two  drops  of  methyl  orange  are  added, 
and  then  hydrochloric  acid  until  one  drop  produces  a  pink. 
Add  i  c.c.  of  cone,  hydrochloric  acid  in  excess.     Heat  the  solu- 
tion to  boiling.     Precipitate  the  molybdenum  in  the  hot  solu- 
tion with  lead  acetate.    Add  also  an  equal  volume  of  a  solution 
of  ammonium  acetate  (50  grams  of  the  salt  made  to  a  volume  of 
100  c.c.  with  water).    Let  the  precipitate  settle  for  an  hour  or 
two.     Cool.     Filter.     Wash  with  hot  water.     Ignite  in  a  plat- 

*  The  molybdenum  can  be  weighed,    also,   as   the   trioxide   as   given   under 
molybdenum  steels. 


ANALYSIS  OF  VANADIUM   STEEL  AND   FERRO-VANADIUM     33 

inum  crucible  at  a  low  red  heat.  Cool  and  weigh  as  lead  molyb- 
date,  which  multiplied  by  26.16  and  divided  by  the  weight 
taken  for  analysis  gives  the  per  cent  of  molybdenum.  (See 
Molybdenum  in  Steel,  page  130.) 

SILICON. 

For  silicon  dissolve  one  gram  of  the  finely  ground  ferro  in 
50  c.c.  1.20  nitric  acid.  Add  30  c.c.  i .:  3  sulphuric  acid  and 
evaporate  to  fumes.  Dissolve  the  sulphates  in  water,  heating 
until  all  but  silicic  acid  is  in  solution.  Filter.  Wash  with 
dilute  hydrochloric,  then  with  water.  Ignite  and  weigh  as 
usual.  If  the  sample  contains  much  silicon  and  does  not  yield 
to  the  nitric  acid,  filter  out  the  insoluble  residue;  wash  it  first 
with  hydrochloric  acid  and  then  with  water;  roast  off  the  paper 
in  a  platinum  crucible.  Fuse  the  residue  with  20  times  its 
weight  of  sodium  carbonate  plus  -gth  its  weight  of  potassium 
nitrate.  Dissolve  the  melt  with  water.  Acidulate  it  with 
hydrochloric  acid  and  add  the  clear  solution  to  the  portion 
dissolved  by  the  nitric  acid,  and  evaporate  all  to  fumes  with 
30  c.c.  of  i  :  3  sulphuric  acid,  and  finish  as  in  low  silicon  ferro- 
vanadium. 

STANDARDIZATIONS  . 

The  writer  prefers  to  standardize  permanganate  of  potassium 
against  recrystallized  oxalic  acid  kept  in  tightly  stoppered 
bottles:  *  1.58  grams  of  potassium  permanganate  are  dissolved 
in  a  liter  flask  with  distilled  water  and  diluted  to  the  mark. 
19.5815  grams  of  double  sulphate  of  iron  and  ammonia,  i.e., 
FeS04,  (NH4)2S04  +  6  H2O,  are  dissolved  in  the  same  manner, 
with  the  addition  of  50  c.c.  of  i  :  3  sulphuric  acid,  and  diluted 
to  one  liter.  Usually  the  relationship  between  these  two  stand- 
ards is  that  from  40.2  to  40.5  c.c.  of  the  permanganate  equal 
40  c.c.  of  the  double  sulphate.  The  vanadium  value  of  the  per- 
manganate standard  is  checked  against  the  oxalic  acid,  and  the 
vanadium  value  of  the  sulphate  standard  is  calculated  from 
its  relation  to  the  permanganate  standard. 

*  Keep  oxalic  acid  in  a  cool  place  to  prevent  loss  of  water  of  crystallization. 


34  CHEMICAL  ANALYSIS  OF   SPECIAL   STEELS 

*  The  1.58  grams  of  permanganate  solution,  theoretically, 
should  be  equivalent  to  2.56  grams  of  vanadium.  Its  actual 
value  is  found  as  follows:  0.1424  gram  of  oxalic  acid  is  dis- 
solved in  about  100  c.c.  of  water  plus  20  c.c.  of  i  :  3  sulphuric 
acid  and  heated  to  80°  C.  The  permanganate  standard  is 
then  added  until  one  drop  produces  a  permanent  pink.  This 
usually  requires  45.45  c.c.  of  the  permanganate.  We  in  the  first 
place  have  the  proportion : 

Oxalic  Acid.  Permanganate. 

63  :  31.6         :  :        0.1424         :        X.. 

This  gives  X  equals  0.07142,  or  0.07142  gram  of  pure  perman- 
ganate will  oxidize  0.1424  gram  of  oxalic  acid.  By  the  above 
titration  it  is  found  that  it  requires  45.45  c.c.  of  the  perman- 
ganate standard  to  oxidize  0.1424  gram  of  oxalic  acid.  Therefore 
each  c.c.  of  the  permanganate  standard  must  contain  0.07142 
divided  by  45.45,  or  0.001571  gram  of  100  per  cent  potassium 
permanganate.  We  thus  obtain  the  final  proportion,  or 

1.58     :     2.56     :  :    0.001571     :    X. 

X  equals  0.002545,  or  i  c.c.  permanganate  solution  equals 
0.002545  gram  of  vanadium. 

The  chromium  value  of  these  standards  is  found  by  adding 
to  2  grams  of  a  plain  carbon  steel  a  weighed  amount  of  recrys- 
tallized  potassium  dichromate.  This  mixture  is  put  through 
the  entire  process  of  an  analysis.  Taking  the  percentage  of 
chromium  in  dichromate  of  potash  as  35.38  per  cent,  the  sul- 
phate standard  is  found  to  have  a  value  that  varies  from  0.00085 
to  0.00087  gram  of  chromium  per  c.c. 

It  must  be  constantly  borne  in  mind  that  to  attain  success 
in  vanadium  and  chromium  titrations,  in  steels,  that  it  is  abso- 
lutely essential  when  coming  back  with  permanganate  to  stop 
with  the  first  3  drops  that  give  a  faint  pink  reflection  that  is 
still  faintly,  but  distinctly,  visible  after  thirty  seconds  stirring. 
Furthermore,  the  next  step  is  to  add  the  ferricyanide  indicator. 
Then  the  ferrous  ammonium  sulphate  is  quickly  added  until 
3  drops  produce  the  first  distinct  darkening  of  the  green  to  a 

*  Read  pages  41  to  42. 


ANALYSIS   OF  VANADIUM    STEEL  AND   FERRQ-VANADIUM     35 


distinct  blue.  Do  not  continue  to  add  the  sulphate  to  a  still 
darker  blue.  In  short,  if  the  pink  end-point  is  overdone,  and 
then  the  blue  one  also,  the  error  is  doubled.  Always  aim  to 
finish  standards,  blanks  and  tests  exactly  as  described. 

The  author  has  had  occasion  to  analyze  the  following  va- 
rieties of  ferro-vanadium  which  will  give  some  idea  of  the  differ- 
ent types  likely  to  be  encountered  by  the  iron  and  steel  analyst : 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

No.  6 

Vanadium 

Per 
cent. 

22    77 

Per 
cent. 

12   4<? 

Per 
cent. 

2tr    n; 

Per 
cent. 

^2    <? 

Per 
cent. 

31   4.8 

Per 
cent. 

23    33 

Carbon  . 

I    74 

o  16 

O   3<C 

2    OQ 

o  08 

4rr 

Manganese  

O  07 

o  46 

O   IO 

o  07 

o  28 

3    3O 

Phosphorus  

0.40 

o  28 

Silicon  

O.6o 

7.65 

1  .02 

O   43 

13    OO 

3   8 

Iron  

74.08 

6s.  54 

62.60 

41  .  SO 

Sulphur 

Oil 

O    $2 

Chromium 

O    22 

Aluminum 

7    31 

41  3 

Copper 

6  24 

Molybdenum.  .  . 

O    SO 

THE  AUTHOR'S   PRESENT   METHOD    OF   TITRATING  VANADIUM 
IN  FERRO-VANADIUM  AND  PLAIN  VANADIUM  STEEL. 

During  four  or  more  years  subsequent  practice  of  the  vana- 
dium method,  given  in  the  preceding  pages  of  Chapter  II,  some 
changes  have  been  made  to  avoid  the  interference  of  any  small 
amounts  of  manganese  present  in  the  solution,  in  the  manganic 
state;  or  chromium  that  may  be  in  the  sample  to  the  extent 
of  o. 20  to  o.i o  per  cent,  or  less;  or  of  uranium.  The  latter  ele- 
ment, when  in  the  solution  to  the  amount  of  several  per  cent, 
forms  objectionable  brown  tints,  seriously  obscuring  the  end 
point  if  the  ferricyanide  indicator  is  added  first;  then  the  sulphate 
standard;  and  then  the  permanganate  standard  to  obtain  the 
old  rose  shade.  Before  this  end  point  is  attained,  the  uranium 
brown  color  has  overshadowed  it.  By  the  following  modifi- 
cation these  interferences  are  avoided. 


36  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

First  from  a  100  c.c.  burette  deliver  into  an  800  c.c.  beaker 
40  c.c.  of  the  sulphate  standard.  Also  pour  in  the  beaker  350 
c.c.  of  distilled  water  and  30  c.c.  of  i  :  3  sulphuric  acid.  Ti- 
trate this  mixture  with  the  permanganate  standard  to  get  the 
relation  between  the  two  standards;  assuming  the  vanadium 
value  of  the  permanganate  as  correct,  that  of  the  sulphate  is 
calculated  from  the  result  of  this  titration.  The  standards 
prepared  as  given  on  pages  33  and  34  should  be  nearly  equiva- 
lent in  vanadium  value. 

Now,  instead  of  adding  the  ferricyanide  indicator  at  the  start, 
the  titration  is  begun  by  adding  the  sulphate  standard  until  all 
brown  or  pink  tints  are  gone  and  a  green  color  begins  to  appear 
due  to  the  partial  reduction  of  the  vanadic  acid  to  the  hypo- 
vanadic  state.  Next,  add  the  permanganate  standard  with 
continued  stirring  until  a  strong  reddish  pink  is  reached;  stir 
well  and  wait  30  seconds  to  insure  a  complete  reaction  between 
the  vanadium  and  the  permanganate  as  the  former  acts  rather 
slowly  at  room  temperature;  make  sure  that  the  red  color 
does  not  fade  perceptibly  during  the  pause.  In  case  a  fad- 
ing is  noted  more  permanganate  must  be  added,  followed 
by  more  stirring,  and  so  on,  until  the  fading  is  no  longer 
noticeable.  However,  such  fading  does  not  occur  as  a  rule 
more  than  once,  if  the  red  end  point  is  approached  rather 
slowly  and  with  much  stirring  after  each  addition  of  the  per- 
manganate standard. 

The  sulphate  standard  is,  again,  dropped  in  to  remove  the 
excess  of  the  permanganate;  this  is  accomplished  by  adding 
the  former  standard,  a  few  drops  at  a  time,  until  the  deep  red 
is  all  gone  and  the  solution  has  taken  on,  in  the  main,  a  yellow 
tint  with  a  very  slight  but  distinct  tan  shade  in  it.  At  this 
stage  2  drops  of  the  permanganate  should  cause  a  reappear- 
ance of  a  slight  suggestion  of  pink,  as  one  looks  down  through 
the  mouth  of  the  beaker.  The  operator  can  then  discharge 
this  very  faint  pink  with  2  drops  of  the  sulphate  standard. 
The  solution  is  now  ready  for  the  titration  proper.  The  read- 
ing of  the  sulphate  burette  is  noted;  the  ferricyanide  indicator 


ANALYSIS   OF  VANADIUM   STEEL  AND  FERRO-VANADIUM     37 

is  poured  in,  and  the  sulphate  standard  is  dropped  in  immedi- 
ately, thereafter,  until  the  green  color  that  forms  is  changed 
to  the  first  deep  blue.  This  dark  blue  is  the  end  point,  and 
should  be  rather  rapidly  approached  to  catch  the  first  change 
from  the  dark  green  to  the  blue.  Of  course  the  solution  is 
stirred  vigorously  during  the  titration.  The  sulphate  used  for 
this  last  titration,  i.e.,  subsequent  to  the  pouring  in  of  the  indica- 
tor, minus  the  blank,  is  the  sulphate  equivalent  of  the  vanadium. 

PLAIN  VANADIUM  STEEL. 

With  a  vanadium  content  of  o.io  to  0.30  per  cent,  take  from 
4  or  5  grams  of  sample  and  proceed  as  described  for  chrome 
vanadium  steel  on  page  7,  using  50  c.c.  of  i  :  3  sulphuric  acid 
to  effect  the  solution  of  the  drillings,  diluting  with  about  20  c.c. 
of  water  to  prevent  the  formation  of  crusts  of  sulphate  of  iron; 
warm  until  no  further  evolution  of  fine  bubbles  of  hydrogen 
is  visible;  and  then  add  75  c.c.  of  1.20  nitric  acid  to  oxidize 
the  ferrous  iron;  heat  until  all  red  fumes  are  gone;  proceed 
further  as  given  on  page  8,  except  that  the  excess  of  the  hydrated 
oxide  of  manganese  is  filtered  out  by  means  of  a  porous  alun- 
dum  thimble,  avoiding  entirely  the  use  of  asbestos  filters.  This 
same  filter  is  now  used  for  this  purpose  in  the  analysis  of  ferro- 
vanadium.  But  very  slight  suction  is  required.  (See  photo  15, 
page  247.) 

The  filtrate  and  washings  can  be  pink  with  an  excess  of  per- 
manganate as  will  be  seen.  The  volume  of  all  tests  and  blanks 
should  be  the  same  and  should  not  exceed  350  c.c.  just  before 
the  titration.  Titrate  the  above  filtrate  in  the  same  manner 
as  given  for  the  ferro-vanadium,  i.e.  discharge  all  pink  or  brown 
tints'  to  a  clear  greenish  yellow  (of  course  the  green  is  not  so 
noticeable  in  steels  as  it  is  in  ferro-vanadium)  by  adding,  at  the 
start,  about  10  or  more  c.c.  of  the  sulphate  standard;  then 
continue  as  in  the  ferro  and  calculate  the  vanadium  from  the 
sulphate  required  to  produce  the  dark  blue  after  the  addition 
of  the  indicator,  less  the  blank  which  for  this  procedure  is,  in 
this  laboratory,  from  0.8  to  0.9  c.c.  for  plain  vanadium  steels. 


38  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

BLANK  TESTS. 

To  obtain  the  blank  test  to  apply  in  the  analysis  of  ferro- 
vanadium  of  from  30  to  40  per  cent  vanadium,  dissolve  200 
mgs.  of  plain  carbon  steel;  and  for  plain  vanadium  steels, 
dissolve  five  grams  of  plain  steel  just  as  directed  for  ferro- vana- 
dium and  plain  vanadium  steel,  respectively.  Put  these  blanks 
through  all  of  the  operations  and  titrations,  noting  the  amount 
of  sulphate  required  to  produce  a  dark  blue  after  the  ferri- 
cyanide  indicator  has  been  added  in  the  order  given.  The 
portion  of  a  c.c.  so  consumed  constitutes  the  blank  to  be  de- 
ducted from  all  tests.  Pay  no  attention  should  the  dark  blue 
of  the  blank  begin  to  fade  in  a  few  minutes.  This  is  caused  by 
the  oxidizing  action  of  the  nitric  acid  left  in  the  solution.  In 
actual  work  containing  vanadium,  the  blue  end  point  does  not 
fade  or  change  so  quickly. 

Blanks  can  also  be  determined  by  difference,  i.e.,  a  known 
amount  of  vanadium  is  added  to  a  plain  steel  and  it  is  then  ana- 
lyzed for  vanadium.  Assume,  for  example,  that  the  value  of 
the  sulphate  standard  is  i  c.c.  equals  0.00254  gram  vanadium; 
further,  that  to  4  or  5  grams  of  plain  steel  have  been  added  30 
mgs.  of  ferro-vanadium  containing  38.23  per  cent  vanadium. 
This  mixture  is  then  analyzed  for  vanadium  and  is  found  to 
consume  5.3  c.c.  of  the  standard  sulphate.  Now  0.3823  X  30 
equals  1 1 .469  mgs.  of  vanadium  and  should  require,  if  there  were 
no  blank,  11.469  divided  by  2.54  equals  4.51  c.c.;  therefore  the 
blank  is  5.3  less  4.51  or  0.79  c.c.,  or  the  blank  to  be  deducted 
from  all  titrations  to  get  the  number  of  c.c.  of  sulphate  con- 
sumed by  the  vanadium  alone. 

CHROME  VANADIUM  STEELS. 

These  steels  are  titrated  as  given  on  pages  8,  9,  30,  and  31. 
On  page  8  the  directions  read  to  completely  reduce  the  chro- 
mium in  the  solution  by  adding  the  sulphate  standard  until 
the  "  chrome  green  no  longer  grows  darker  (that  is,  the  green 
shade  no  longer  gains  intensity)  and  2  or  3  c.c.  more  to  insure 
excess."  The  following  example  shows  how  the  operator  can  be 


ANALYSIS  OF  VANADIUM   STEEL  AND   FERRO-VANADIUM     39 

sure  that  he  has  an  excess  of  the  sulphate  and  that,  therefore, 
no  chromium  remains  in  the  chromic  acid  state  which  would 
consume  some  of  the  sulphate  standard  and  be  counted  as  vana- 
dium. This  example  is  particularly  useful  when  steels  high  in 
vanadium  are  to  be  dealt  with,  i.e.,  containing  from  0.50  to  2.00 
per  cent  vanadium  and  over: 

EXAMPLE. 

FIRST     PART     OF     THE     TITRATION     TO     OBTAIN     THE     CHROMIUM.        (MADE     BEFORE 
ADDING  THE   FERRICYANIDE.) 

KMn04  Double  Sulphate. 

21  c.c.  second  reading  of  the  burette  97.2  c.c. 

9  c.c.  first  reading  of  the  burette  0.2  c.c. 

12  c.c.  (A)  97.0  c.c. 

1 2.0  (A) 
85.0  c.c. 

85.0  X  0.00085  X  ioo  divided  by  2  equals  3.61  per  cent  chromium  when  2  grams 
are  taken. 

SECOND   PART   OF   THE   TITRATION   TO   OBTAIN   THE   VANADIUM   PERCENTAGE. 

(MADE  IMMEDIATELY  AFTER  ADDING  THE  FERRICYANIDE  INDICATOR.) 

Sulphate  used  by  the  vanadium. 

8.2  c.c.  second  reading  of  the  burette. 

i.o  c.c.  first  reading  of  the  burette. 

7.0  c.c.  or  (B) 

0.8  c.c.  (blank) 

6.2  c.c.  6.2  X  0.00254  X  ioo  divided  by  2  equals  0.78  per  cent  V. 

(A)  should  always  be  several  c.c.  in  excess  of  (B)  to  insure  no  chromium  being 
dragged  over  into  the  second  part  of  the  titration  in  the  unreduced  state  and 
counted  as  vanadium. 

THE  TITRATION  OF  CHROME  VANADIUM  STEELS  IN  A  MAN- 
NER SIMILAR  TO  FERRO-VANADIUM. 

In  this  laboratory  these  steels  are  now  frequently  titrated 
for  vanadium  by  oxidizing  back  the  vanadium  (after  the  usual 
excess  of  the  double  sulphate  has  been  dropped  in  the  manner 
just  described  to  reduce  both  the  Cr  and  V)  by  adding  the  per- 
manganate standard  until  a  strong  pink  is  obtained.  The 
solution  is  then  stirred  for  a  half  minute  vigorously  to  note  if 
there  is  a  perceptible  fading  of  the  permanganate.  If  there  is  a 


40  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

noticeable  fading,  then  more  permanganate  is  added  to,  again, 
obtain  a  strong  pink  which  must  show  no  perceptible  change 
after  thirty  seconds  further  stirring.  Then  the  excess  of  per- 
manganate is  slowly,  drop  by  drop,  taken  up  by  adding,  with 
prolonged  stirring,  the  sulphate  standard  until  two  drops  leave 
only  the  faintest  suggestion  of  a  pink  as  one  looks  down  through 
the  solution.  When  the  right  point  is  reached,  two  drops  of 
the  permanganate  should  again  give  a  distinct  increase  of  the 
pink  shade,  even  after  the  prescribed  amount  of  stirring.  Two 
drops  of  the  sulphate  standard  should  reduce  this  pink  again 
to  the  faint  pink.  The  solution  can  be  thus  adjusted  back  and 
forth  to  suit  the  operator,  to  a  nicety.  It  is  then  ready  for  the 
addition  of  the  indicator  and  the  final  titration  to  obtain  the 
number  of  c.c.  used  by  the  blank  plus  the  vanadium,  or  (B). 

THE  DETERMINATION  or  THE  CHROMIUM  VALUE  OF  THE  DOUBLE 
SULPHATE,  AND  THE  VANADIUM  BLANK  FOR  CHROMIUM  VANA- 
DIUM STEELS  BY  MEANS  OF  A  KNOWN  MIXTURE. 

Suppose  the  above  values  are  needed  for  a  steel  of  about 
3  or  4  per  cent  chromium  and  0.50  to  i.oo  per  cent  vanadium; 
then  a  suitable  mixture  would  be  2  grams  of  plain  carbon  steel, 
free  from  vanadium,  170  milligrams  of  c.p.  crystals  of  potassium 
dichromate  and  0.075  gram  of  ferro-vanadium  of  21.8  per  cent  V. 
The  analytical  data  obtained  in  this  particular  case,  after  put- 
ting the  mixture  through  the  regular  operations  given  in  the 
foregoing  pages,  are  found  below,  together  with  the  calculations: 

KMnO4  used  in  the  first  part  The  double  sul- 

of  the  titration  to  obtain  phate  used  by  the 

the  chromium  value.  chromium,  etc. 

65.8  c.c  81.0  c.c. 

56.2  c.c.  00.4  c.c. 

9.6  c.c.  80.6  c.c. 

80.6  c.c. 
9.6  c.c. 
71.0  c.c.  used  by  the  chromium,  alone. 

Potassium  dichromate  contains  35.35  per  cent  chromium; 
therefore  0.170  X  0.3535  divided  by  71.0  equals  0.00847,  or  I  c-c- 
of  the  double  sulphate  equals  0.00847  gram  of  chromium. 


ANALYSIS   OF   VANADIUM*  STEEL  AND  FERRO-VANADIUM     41 

The  second  part  of  the  titration  made  immediately  after  add- 
ing the  ferricyanide  indicator  gave  the  following  readings  of  the 
sulphate  consumed  by  the  vanadic  acid  in  the  solution : 

88.2  c.c.  second  reading  of  burette. 
81.0  c.c.  first  reading  of  burette. 
7.2  c.c.  sulphate  used  by  V2O5  and  the  blank. 

0.075  X  0.218  equals  0.01635  gram  of  vanadium  added.  Taking 
the  vanadium  value  of  the  sulphate  standard  as  found  by  stand- 
ardizing it  against  sodium  oxalate,  as  given  on  page  42,  or  i  c.c. 
equals  0.002536  gram  of  vanadium,  one  obtains  by  dividing  the 
vanadium  added,  or  0.01635,  by  0.002536  a  quotient  of  6.4; 
hence  7.2  c.c.  minus  6.4  c.c.  equals  0.8  c.c.  or  the  sulphate  blank 
to  be  deducted  from  the  total  amount  of  sulphate  consumed  in 
the  vanadium  titration  of  the  above  range  of  chrome  vanadium 
steels. 

THE  STANDARDIZATION  OF  THE  DOUBLE  SULPHATE  FOR 
VANADIUM  BY  SODIUM  OXALATE. 

(A)  The  strength  of  the  standards  per  liter  are  the  same  as 
given  on  page  33.     150  mgs.  of  c.p.  sodium  oxalate  prepared 
according  to  Sorensen  are  weighed  into  a  beaker,  and  dissolved 
in  20  c.c.  of  i  :  3  sulphuric  acid  plus  150  c.c.  of  distilled  water. 
(This  sodium  oxalate  can  be  obtained  for  a  small  fee  from  the 
Bureau  of  Standards  at  Washington,  D.  C.,  or  can  be  prepared 
by  recrystallizing  the  c.p.  salt  offered  by  the  dealers.)     The 
mixture  of  sodium  oxalate  is  heated  to  about  80°  C.  and  titrated 
with  the  permanganate  standard  solution  until  one  drop  of  the 
same  changes  the  mixture  to  the  faintest  pink. 

(B)  Also  a  measured  amount  of  the  permanganate  standard 
is  placed  in  a  beaker  together  with  20  c.c.  of  i :  3  sulphuric  acid 
and  titrated  with  the  double  sulphate  standard  until  the  pink 
color  just  disappears  to  get  the  ratio  between  the  two  stand- 
ards.    (10  FeS04  +  2  KMnO4  +  8  H2SO4  =  5  Fe2  (S04)3  +  8H2O 
+  K2S04  +   2  MnSO4.)     The  following  equation  explains  the 
reaction  occurring  in  (A) : 

2  KMn04  +  5  Na2C2O4  +  13  H2SO4  =  K2SO4  +  2  MnSO4  +  10 
NaHSO4  +  8  H2O  +  10  CO2 (i) 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


Equation  (2)  shows  the  relation  between  potassium  perman- 
ganate and  vanadium: 

5  (VO)2(SO4)2  +  2  KMn04  +  8  H2S04  =  5  (VO)2(SO4)3  +  K2S04-h 
2  MnS04 -f- 8  H20.    .     . (2) 

Equation  (i)  shows  that  2  KMnO4  are  equivalent  to  5  Na2C204. 

Equation  (2)  shows  that  2  KMnO4  are  equivalent  to  loV; 
therefore 

5  Na2C2O4    are  equivalent  to     10  V. 
(670)  (510) 

The  following  proportion  will  hence  give  the  vanadium  equiv- 
alent of  0.150  gram  of  sodium  oxalate: 

670     :     510     :. :    0.150     :    X. 
X  =  0.11417  gram  of  vanadium. 

By  titration  (A)  it  was  found  that  45.35  c.c.  were  required  of 
the  permanganate  standard  to  combine  with  0.150  gram  of 
oxalate  so  that  i  c.c.  of  the  permanganate  equals  0.11417  di- 
vided by  45.35,  or  0.002517  gram  of  vanadium.  By  titration 
(B)  it  was  found  that  40  c.c.  of  the  sulphate  were  equivalent 
to  40.3  of  the  permanganate;  therefore  i  c.c.  of  the  double 
sulphate  equals  0.002517  X  40.3  divided  by  40,  or  0.002536 
gram  of  vanadium.  The  double  sulphate  standard  should 
be  tested  according  to  (B)  on  each  occasion  that  it  is  used  and 
its  vanadium  value  adjusted  according  to  the  relation  so  found. 

SOME  RECENT  ANALYSES  OF  FERRO- VANADIUM. 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

c 

Per  cent. 
O  06 

Per  cent. 
O.O? 

Per  cent. 
0.08 

Per  cent. 

o.  13 

Per  cent. 
o.  19 

Mn 

O   14 

O.l8 

o.  19 

O.22 

4.11 

Si  

1  .  52 

0.97 

0.66 

0.92 

8.35 

V  

40.41 

40.54 

39.40 

39.50 

35.62 

Ni  

0.72 

1  .32 

1.68 

2.50 

7.74 

Cu 

None 

None 

None 

None 

Al. 

O.95 

I  .  22 

i  .33 

0.92 

i  .43 

Mo  

0.92 

i  .00 

0.92 

O.6O 

Fe  

54.65 

54-  IO 

5S-20 

54.50 

42.60 

p 

O    13 

s               

0.65 

0.20 

For  the  determination  of  Vanadium  in  Vanadium  Ores,  see  page  301. 


CHAPTER  III. 

FERRO-TITANIUM  AND  TITANIUM  STEEL. 

SOLUBLE  FERRO-TITANIUM. 

*  Titanium.    When  ferro- titanium  of  low  titanium  content, 
8  per  cent  titanium  for  example,  dissolves  almost  completely 
in  sulphuric  acid,  proceed  in  the  following  manner:  Dissolve  from 
0.4  to  0.5  gram  of  drillings  in  30  c.c.  i  :  3  sulphuric  acid.     Filter 
and  keep  the  insoluble  residue  if  any.     After  washing  it  free 
from  blue  iron  test  with  potassium  ferricyanide,  it  is  fused  with 
twenty   times   its   weight   of   sodium   carbonate.     (Use    i  :  10 
sulphuric  acid  for  washing.) 

Nearly  neutralize  the  nitrate  and  washings  with  i  :  3  ammo- 
nia water.  Dilute  to  300  c.c.  with  water.  Add  to  the  cold 
solution  5  grams  of  sodium  thiosulphate  f  dissolved  in  water. 
Boil  gently  for  half  an  hour,  and  filter,  using  paper  pulp.  Wash 
with  sulphurous  acid  water  (2  c.c.  of  cone,  sulphurous  acid  to 
500  c.c.  of  water)  until  no  test  for  iron  is  obtained.  The  washed 
precipitate  is  ignited  and  fused  with  twenty  times  its  weight  of 
sodium  carbonate.  Keep  the  fusion  molten  at  a  bright  red 
heat  for  forty  minutes.  Dissolve  in  water  in  a  platinum  dish; 
add  ashless  paper  pulp;  filter;  wash  thirty  times  with  sodium 
carbonate  water.  Heat  the  filtrate  to  boiling  in  a  beaker;  add 
hydrochloric  acid  drop  by  drop  to  the  filtrate,  and  note  if  a  white 
precipitate  forms  at  any  time  before  the  filtrate  becomes  acid. 
If  a  precipitate  forms,  then  roast  the  sodium  titanate  to  free  it 
from  pulp,  and  fuse  again  as  before;  filter;  wash;  and  treat 
the  now  aluminum-free  titanate  as  follows : 

*  That  is,  5  grams  of  "thio"  for  every  50  mgs.  of  Ti  likely  to  be  in  the  solution, 
t  Read  pages  57  to  60. 

43 


44  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

*  Spread  filter  and  residue  in  a  small  dish  and  cover  it  with 
about  30  c.c.  of  i  :  3  sulphuric  acid.     It  is  heated  on  a  water  bath 
for  half  an  hour,  or  until  all  but  the  filter  pulp  is  in  solution.    The 
pulp  is  filtered  out  and  washed  thirty  times  with  dilute  i  :  20 
sulphuric  acid  water  and  then  with  water  until  the  washings 
no  longer  show  a  test  for  sulphuric  acid  with  barium  chloride 
solution.     Burn  this  washed  pulp  to  make  sure  that  all  titanate 
is  dissolved.     The   filtrate   and   washings   are  nearly  neutral- 
ized with  ammonia;   5  grams  of  sodium  thiosulphate  are  added; 
and  the  titanic  acid  is  precipitated  and  washed  as  before  with 
sulphurous  acid  wash.     It  is  given  forty  washings  and  ignited 
and  weighed  as  TiC>2  plus  a  little  SiC>2.     The  residue  is  treated 
with  from  5  to   10  drops  of  cone,  sulphuric  acid.     The  cru- 
cible   is   filled    about    three-fourths   full    of    c.p.   hydrofluoric 
acid   and   freed   from  silica   as   in   steels.     The   weight   thus 
obtained,   being  the   pure   TiO2,   is  'multiplied   by  60.04   and 
divided  by  the  weight  taken  for  analysis  to  obtain  the  per- 
centage of  titanium. 

The  small  insoluble  residue  obtained  from  the  first  solution 
of  the  drillings  in  i  :  3  sulphuric  acid  is  fused  with  twenty  times 
its  weight  of  sodium  carbonate.  The  melt  is  dissolved  in  water; 
washed  thirty  times  with  sodium  carbonate  water.  The  filter 
and  residue  are  spread  out  in  a  small  dish  with  20  c.c.  i  :  3  sul- 
phuric acid  and  heated  on  a  water  bath  for  thirty  minutes  to 
dissolve  the  titanate  of  soda.  The  paper  pulp  is  then  removed 
by  filtration,  and  the  filter  is  washed  thirty  times  with  i  :  20 
sulphuric  acid.  The  filtrate  and  washings  from  the  pulp  are 
made  nearly  neutral  with  ammonia  water;  5  grams  of  "thio" 
are  added;  and  the  solution  is  boiled  gently  for  half  an  hour. 
The  titanic  acid  thus  obtained  is  combined  with  the  main  pre- 
cipitate obtained  in  like  manner  with  sodium  thiosulphate. 
It  is  roasted  with  it  just  before  it  is  fused  the  first  time  with 
sodium  carbonate  to  remove  alumina. 

*  Or  the  filter  and  residue  can  be  roasted;  fused  with  10  gms.  of  KHSO4;  the 
melt  dissolved;    filtered;    the  filtrate  and  washings  nearly  neutralized  and  the  Ti 
precipitated  as  before  with  "thio." 


FERRO-TITANIUM  AND  TITANIUM  STEEL  45 

SULPHUR,  PHOSPHORUS  AND  ALUMINUM  *  IN  FERRO-TITANIUM. 

The  sulphur,  phosphorus  and  aluminum  in  all  varieties  of 
ferro-titanium  can  be  best  obtained  by  fusing  the  drillings  or 
powdered  material  in  a  platinum  crucible  with  20  grams  of 
sodium  carbonate  ground  thoroughly  with  four  grams  of  potas- 
sium nitrate.  A  double  fusion  should  be  made.  Fuse  one 
gram  of  sample  as  above.  When  the  melt  is  in  a  state  of  quiet 
fusion,  keep  it  at  a  bright  red  heat  for  30  minutes  longer. 
Dissolve  the  fusion  in  a  porcelain  or  platinum  dish  in  hot  water. 
A  platinum  dish  is  best  for  this  work.  If  the  supernatant  fluid 
in  the  dish  is  tinged  with  green,  or  in  high  per  cents  of  man- 
ganese of  i  per  cent  and  above  is  a  deep  green,  then  add  a 
few  drops  of  absolute  alcohol  which  will  convert  the  green 
manganate  of  soda  into  the  brown  oxide  of  manganese.  Con- 
tinue to  warm  the  solution  until  all  green  color  is  gone  and  the 
liquid  is  colorless.  This  procedure  leaves  all  of  the  manganese 
with  the  iron  and  titanium.  Wash  the  residue  with  sodium 
carbonate  water.  Roast  it;  fuse  again;  dissolve;  treat  with 
alcohol;  filter;  wash  and  combine  the  two  filtrates  and  the 
washings  in  one  beaker.  Add  to  this  solution,  which  contains 
all  of  the  sulphur,  phosphorus  and  aluminum  in  the  alloy, 
i  :  i  hydrochloric  acid  until  the  solution  is  slightly  acid.  Heat 
to  boiling.  Add  a  slight  excess  of  ammonia  which  will  precipi- 
tate all  of  the  aluminum  as  hydroxide  and  phosphate.  This, 
precipitate,  if  present  in  considerable  quantity,  will  carry  all 
of  the  phosphorus  present  in  the  ferro.  It  is  washed  with  am- 
monium nitrate  water  and  dissolved  off  the  filter  at  once  with 
hot  i  :  i  hydrochloric  acid.  The  filter  is  washed  free  of  acid 
and  should  be  burned,  weighed,  and  its  weight  added  to  the  final 
weight  of  the  A12O3  +  SiO2. 

It  is  claimed  that  aluminum  precipitated  from  solutions  con- 
taining sodium  chloride  carries  with  it  a  certain  amount  of  soda 
salt  that  cannot  be  removed  from  it  by  wash  water.  This  is 

*  Aluminum  can  also  be  obtained  as  given  on  page  23,  except  that  the  ferro 
is  dissolved  in 


46  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

why  the  aluminum  hydroxide  is  redissolved  in  i  :  i  hydro- 
chloric acid.  It  is  then  precipitated  hot  with  ammonia  in 
slight  excess  and  washed  with  ammonium  nitrate  water;  ignited 
and  weighed,  as  Al2Os  +  P2C>5  +  Si02.  The  silica  is  removed 
by  hydrofluoric  acid  and  a  few  drops  of  sulphuric  acid  as  usual, 
and  the  residue  is  ignited  and  weighed  again  as  A12O3  -f  P205. 
This  residue  is  fused  with  twenty  times  its  weight  of  sodium 
carbonate.  The  melt  is  dissolved  in  water;  acidulated  with 
nitric  acid  in  slight  excess.  The  volume  is  made  up  to  50  c.c.; 
boiled  with  KMnO4;  and  the  phosphorus  precipitated  as  usual 
with  molybdate  solution.  The  number  of  milligrams  of  phos- 
phorus found  is  calculated  to  percentage  and  also  to  P2Os. 
The  milligrams  of  the  latter  are  deducted  from  the  weight  of 
A12O3  +  P2O5  and  the  remainder  is  multiplied  by  53.03  and  di- 
vided by  the  weight  taken  for  analysis  to  obtain  the  percentage  of 
aluminum  in  the  alloy.  (See  page  332,  Phosphorus  in  Graphite.) 

If  the  original  filtrates  from  the  double  fusion  show  very 
little  or  no  aluminum  on  being  treated  with  hydrochloric  acid 
until  the  hot  solution  is  only  faintly  alkaline,  then  there  is  a 
possibility  that  the  filtrate  from  this  aluminum  may  still  con- 
tain phosphorus.  To  obtain  this  phosphorus  a  solution  of 
ferric  chloride  free  of  phosphorus  and  sulphur  is  added  to  the 
filtrate  from  the  small  quantity  of  aluminum  or  to  the  slightly 
acid  solution,  if  no  aluminum  hydroxide  formed. 

This  solution,  which  should  be  faintly  colored  with  ferric 
chloride  and  slightly  acid,  is  precipitated  hot  with  a  small  excess 
of  ammonia.  The  precipitate  is  filtered  out;  washed  with  hot 
water;  is  dissolved  off  the  filter  with  a  little  hot  1.20  nitric  acid. 
The  filter  is  washed  free  of  iron  test,  using  potassium  sulpho- 
cyanate  for  the  detection  of  iron  in  the  washings.  The  dilute 
nitric  acid  wash  water  is  used.  (See  Phosphorus  in  Steel,  page 
257.)  Concentrate  the  filtrate  and  washings  to  40  c.c.  Boil 
with  a  little  permanganate;  clear  with  ferrous  sulphate;  and 
finish  as  in  steels.  The  phosphorus  found  in  the  iron  precipi- 
tate plus  that  found  with  the  aluminum  hydroxide,  if  any  formed, 
equals  the  total  phosphorus  in  the  ferro. 


FERRO-TITANIUM  AND  TITANIUM  STEEL  47 

The  filtrate  from  the  aluminum  hydroxide,  or  iron  hydroxide, 
or  both,  is  made  slightly  acid  with  hydrochloric  acid  and  evap- 
orated to  dryness  in  a  600  c.c.  casserole.  Ten  c.c.  of  i  :  i 
hydrochloric  acid  are  added  to  the  dry  residue.  It  is  heated 
with  a  cover  on  the  dish;  200  c.c.  of  water  are  added;  and  the 
dish  is  heated  nearly  to  boiling,  or  until  all  of  the  salt  is  dis- 
solved. The  solution  is  filtered.  The  filter  is  washed  with 
i  :  10  hydrochloric  acid.  The  filtrate  and  washings  are  pre- 
cipitated with  20  c.c.  of  a  saturated  solution  of  barium  chloride. 
The  barium  sulphate  formed  is  allowed  to  settle  twelve  hours. 
It  is  filtered  with  a  little  pulp;  washed  free  from  chloride  tests 
with  water  only;  burned  in  a  weighed  platinum  crucible; 
moistened  with  a  drop  or  two  of  i  :  3  sulphuric  acid,  as  the 
burning  of  the  paper  always  reduces  a  little  of  the  barium  sul- 
phate to  BaSO3.  .It  is  ignited  again  and  weighed  as  BaS04, 
which  weight,  multiplied  by  13.73  and  divided  by  the  weight 
taken  for  analysis,  gives  the  percentage  of  sulphur  in  the  sample. 
Deduct  a  blank  due  to  the  fluxes  and  acids  used.  Blanks 
should  always  be  made,  as  sodium  carbonate  and  acids  are 
liable  to  contain  sulphates,  iron  and  aluminum. 

IRON  IN  SOLUBLE  FERRO-TITANIUM. 

Dissolve  0.5  gram  of  sample  in  i  :  3  sulphuric  acid.  If  there 
be  any  insoluble  residue  that  is  not  white,  filter  the  same  out 
and  wash  it  with  dilute  sulphuric  acid.  Roast  it.  Fuse  it 
with  potassium  bisulphate.  Dissolve  the  melt  in  dilute  sulphuric 
acid  and  add  it  to  the  filtrate  and  washings  from  the  insoluble 
residue.  Dilute  the  slightly  acid  filtrate  and  washings  to  200 
c.c.  Pass  hydrogen  sulphide  through  the  same  until  the  iron  is 
entirely  reduced.  It  will  be  colorless  when  hot.  The  reduction 
will  take  about  an  hour,  with  the  gas  passing  at  a  rather  rapid 
rate.  Filter  the  solution  into  an  800  c.c.  boiling  flask.  Wash 
the  filter  with  i  :  10  sulphuric  acid  until  free  of  iron  test.*  Pass 

*  The  residue  on  this  filter  will  contain  all  of  the  copper  present  which  can  be 
roasted  and  finished  as  in  steels  for  Cu. 


48  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

hydrogen   sulphide   through   this   nitrate   for  one  hour  more. 
(Saturate  the  acid  wash  with  H2S  before  using.) 

Now  pass  a  stream  of  carbon  dioxide  through  the  solution, 
keeping  the  same  at  boiling  temperature  during  the  time  that 
the  CO2  is  passing.  When  a  piece  of  filter  paper,  moistened  with 
a  water  solution  of  lead  acetate,  is  no  longer  discolored,  even 
slightly,  when  held  in  the  neck  of  the  flask,  the  excess  of  hy- 
drogen sulphide  is  all  driven  out.  Place  the  flask  in  cold  water 
with  the  stream  of  carbon  dioxide  still  passing  through  it.  The 
glass  tube  that  carries  the  H2S  and  C02  into  the  fluid  should, 
of  course,  reach  nearly  to  the  bottom  of  the  boiling  flask.  When 
the  contents  of  the  flask  are  cold,  titrate  with  standard  perman- 
ganate of  potash  until  one  or  two  drops  yield  a  pink  color  that 
is  permanent  for  several  minutes.  The  same  standard  that 
is  used  for  titrating  iron  in  ferro-vanadium  can  be  utilized  in 
this  determination.  One  c.c.  of  the  standard  equals  0.00556 
gram  of  metallic  iron. 

MANGANESE  IN  FERRO-TITANIUM  SOLUBLE  IN  SULPHURIC 

ACID. 

Dissolve  o.ioo  gram  in  10  c.c.  i  :  3  sulphuric  acid.  Add 
10  c.c.  concentrated  nitric  acid.  Boil  off  red  fumes.  Dilute 
to  35  c.c.  with  water  and  finish  as  in  steels.  This  applies  to 
manganese  not  in  excess  of  i  per  cent.  Use  0.05  gram  for  man- 
ganese content  exceeding  i  per  cent.  Accurate  to  2  per  cent 
Mn.  For  higher  percentages  of  manganese  dissolve  i  gram 
of  sample  in  30  c.c.  i  :  3  sulphuric  acid.*  Oxidize  by  boiling 
with  10  c.c.  cone,  nitric  acid  and  i  gram  of  potassium  chlorate. 
Add  60  c.c.  i  :  3  sulphuric  acid  and  evaporate  to  thick  fumes. 
Cool,  add  water  and  heat  until  all  is  dissolved  except  perhaps 
some  of  the  titanic  oxide  and  silicic  acid.  Be  sure  that  all  iron 
and  manganese  sulphates  are  in  solution.  Wash  the  cold  solu- 
tion into  a  liter  flask.  Fill  the  flask  one-half  full  with  distilled 
water.  Add  a  rather  thick  paste  of  manganese-free  zinc  oxide 

*  One  can  also  finish  from  this  stage  on  as  directed  on  page  278  by  the  author's 
method  for  manganese  above  2  per  cent. 


FERRO-TITANIUM   AND   TITANIUM    STEEL  49 

and  distilled  water.  Continue  the  addition  of  the  zinc  oxide 
until  the  iron  and  titanium  settle  out  well,  avoiding  any  unnec- 
essary excess  of  the  zinc  oxide.  Cool,  if  necessary,  to  the  tem- 
perature of  the  room,  and  dilute  the  contents  to  the  liter  mark 
with  distilled  water.  Mix  ten  times,  inverting  the  stoppered 
flask  each  time. 

Permit  the  precipitate  to  settle  for  a  half -hour  with  the  flask 
in  an  inclined  position.  Pour  the  supernatant  fluid  through  a 
large,  dry  filter  into  a  dry  beaker.  Use  two  filters  to  hasten 
matters.  Rinse  a  hundred  c.c.  pipette  three  times  with  por- 
tions of  the  filtrate.  Then  draw  out  a  300  c.c.  portion  and  a 
400  c.c.  portion.  Place  these  in  separate  boiling  flasks,  label- 
ing them  300/1000  and  400/1000,  respectively.  Add  two 
drops  of  1.20  nitric  acid  to  each  of  these  aliquot  parts.  Heat 
the  300  c.c.  to  boiling,  and  titrate  with  standard  permanganate 
of  potassium,  adding  a  little  at  a  time.  Shake  thoroughly  with 
each  addition  of  the  permanganate  solution,  reheating  the  solu- 
tion between  times.  When  three  drops  finally  produce  a  slight 
but  distinct  pink  color  in  the  hot  supernatant  fluid,  after  a 
reheating  and  thorough  shaking,  the  end  point  is  reached.  De- 
duct 0.2  c.c.  from  the  total  permanganate  used.  Multiply  its 
value  per  c.c.  in  milligrams  of  iron  by  0.2945  to  find  its  value 
in  milligrams  of  manganese.* 

Titrate  the  400  c.c.  part  in  like  manner  and  average  the  two 
results,  calculating  them  as  3/10  and  4/10  of  a  gram,  respec- 
tively. (See  also  Mn  in  Insoluble  Ferro-Titanium.) 

STANDARDIZATION  OF  THE  PERMANGANATE  SOLUTION  FOR 
IRON  AND  MANGANESE. 

Weigh  3.16  grams  of  c.p.  potassium  permanganate  crystals 
into  a  liter  flask.  Dissolve  in  distilled  water  and  dilute  to  liter 
mark. 

Weigh  0.2850  gram  of  c.p.  recrystallized  oxalic  acid  into  a 
200  c.c.  beaker.  Dissolve  the  crystals  in  100  c.c.  of  hot  water. 

*  The  following  reaction  shows  how  Volhard's  method  proceeds:  3  MnSO4  + 
2  KMnO4  +  2  ZnO  =  K2SO4  +  5  MnOa  +  2  ZnSO4. 


50  CHEMICAL  ANALYSIS  OF   SPECIAL   STEELS 

Add  30  c.c.  i  :  3  sulphuric  acid  and  titrate  this  hot  solution  with 
the  permanganate  solution.  This  latter  should  not  be  stand- 
ardized for,  at  least,  twelve  hours  after  it  has  been  dissolved 
and  made  up  to  i  liter. 

This  amount  of  oxalic  acid  will  require  usually  45.50  c.c.  of 
permanganate  of  the  above  strength  to  render  it  a  faint  pink 
that  is  permanent  for  several  minutes.  As  the  oxalic  value 
of  a  permanganate  solution  multiplied  by  8/9  gives  its  iron 
value  therefore  the  latter  is  found  by  this  calculation:  0.2850  -r- 
45.50  X  8/9  =  0.005567,  or  i  c.c.  of  the  permanganate  equals 
0.005567  gram  of  metallic  iron.  This  value  multiplied  by  0.2945 
yields  the  value  of  the  same  solution  in  grams  of  manganese,  or 
0.005567  X  0.2945  =  0.001639  gram  of  manganese.  For  check 
0.280  gram  oxalic  acid  took  44.8  c.c.  KMnCX,  or  0.280  -f-  44.8  X 
8/9  =  0.005555  and  °-°°5555  X  0.2945  =  0.001636,  or  i  c.c.  = 
0.001636  gram  of  manganese.  Average  iron  value  equals  0.00556 
gram  and  average  manganese  value  equals  0.001637  gram  per 
c.c.  Compare  the  theoretical  factor  for  manganese  with  that 
found  by  standardizing  the  permanganate  standard  by  put- 
ting a  ferro-manganese,  containing  a  known  per  cent  of  man- 
ganese, through  the  identical  process  of  fusion  with  bisulphate; 
precipitation  with  zinc  oxide,  etc.  (See  Analysis  of  Ferro- 
Manganese,  page  188.) 

SILICON  IN  SOLUBLE  FERRO-TITANIUM. 

Dissolve  i  or  2  grams  of  drillings  as  .in  steels.  Evapo- 
rate to  fumes  of  sulphuric  acid.  Dissolve  in  water.  Filter, 
wash,  ignite,  weigh,  evaporate  with  a  few  drops  of  cone,  sul- 
phuric acid,  and  the  usual  amount  of  hydrofluoric  acid.  Ignite 
and  calculate  the  loss  of  weight  as  silicon.  Should  a  white 
coating  appear  on  the  lid  of  the  crucible  when  the  sulphuric 
acid  is  being  driven  off,  it  means  that  there  has  not  been  a 
sufficient  amount  of  sulphuric  acid  added,  some  of  the  titanium 
having  volatilized  as  fluoride. 

In  such  event,  repeat  the  analysis,  using  a  little  more  sulphuric 
acid  with  the  hydrofluoric  acid. 


FERRO-TITANIUM   AND  TITANIUM   STEEL  51 

NICKEL,  VANADIUM  AND  CHROMIUM. 

These  elements  are  determined  in  soluble  ferro-titanium  as 
in  V,  Ni  and  Cr  steels.  See  pages  7,  30,  31  and  39.  Mix  con- 
siderable washed  asbestos  pulp  with  the  slimy  mixture  of  silicic 
and  titanic  acids  before  filtering  out  the  excess  of  manganese 
oxide,  in  the  Cr  and  V  determinations.  Add  paper  pulp  and 
filter  off  the  titanic  acid,  etc.,  before  adding  the  citric  acid,  in 
the  Ni  analysis. 

CARBON  IN  SOLUBLE  FERRO-TITANIUM. 

Some  ferro-titaniums  of  low  silicon  content  can  be  completely 
decarbonized  at  950°  C.  in  a  fused  silica  tube  with  oxygen.  See 
Electric  Combustion  Furnace,  page  224.  It  is  safer  to  burn 
the  sample  in  red  lead.  Burn  i  or  2  grams  of  thin  drillings 
or  3O-mesh  powder  with  4  grams  of  red  lead. 

INSOLUBLE  FERRO-TITANIUM. 

Carbon,  sulphur  and  phosphorus  are  determined  as  given 
in  the  analysis  of  soluble  ferro-titanium. 

SILICON  AND  TITANIUM. 

These  elements  are  best  separated  by  fusion  of  0.5  gram  of 
the  finely  ground  substance  with  15  grams  of  acid  potassium 
sulphate  in  a  40  c.c.  platinum  crucible.  This  fusion  is  highly 
satisfactory  if  conducted  with  a  little  experience.  Heat  the 
crucible  very  gradually  at  first,  using  the  white  flame  of  an 
argand  burner.  Keep  the  melt  below  redness  until  all  of  the 
water  has  been  driven  out  of  the  flux  without  sputtering.  When 
slight  fumes  of  sulphuric  anhydride  begin  to  make  their  appear- 
ance the  heat  can  be  increased  to  low  redness.  Maintain  this 
temperature  until  the  substance  is  in  a  state  of  clear  fusion, 
and  is  a  pure  yellow,  free  of  all  black  specks. 

If  the  argand  burner  flame  is  properly  adjusted,  this  operation 
can  be  going  on  with  only  occasional  attention.  When  all  black 
is  gone,  raise  the  heat  until  fumes  of  sulphuric  anhydride  come 
off  briskly  when  the  lid  is  lifted  slightly. 


52  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Then  turn  off  the  heat  and  run  the  melt  well  up  the  sides. 
Place  the  crucible  in  a  250  c.c.  casserole  with  50  c.c.  of  water 
plus  50  c.c.  of  i  :  3  sulphuric  acid.  Dissolve  with  heat.  Filter 
out  the  white  insoluble  residue;  wash  it  free  of  iron  and  sul- 
phate, using  barium  chloride  solution  for  the  latter  tests  and 
KCNS  for  the  former.  Ignite  it  in  a  weighed  crucible.  Weigh 
as  Si02  plus  a  little  TiO2.  Evaporate  with  HF1  and  a  few  drops 
of  H2S04  and  calculate  the  loss  of  weight  to  silicon.  Keep  the 
non- volatile  portion  to  add  to  the  main  portion  of  Ti02. 

The  nitrate  and  washings  from  the  silica  are  made  nearly 
neutral  with  ammonia  and  precipitated  with  thiosulphate  of 
soda,  and  finished  as  in  soluble  ferro-titanium  for  Ti. 

IRON. 

Fuse  0.5  gram  as  for  silicon.  Reduce  with  H2S  and  finish 
as  given  under  the  soluble  ferro. 

ALUMINUM. 

Proceed  by  fusion  as  given  under  aluminum  in  soluble  ferro- 
titanium. 

MANGANESE  IN  INSOLUBLE  FERRO-TITANIUM. 

If  the  percentage  of  manganese  is  under  two  per  cent,  fuse 
o.ioo  or  0.05  gram  with  twenty  times  this  weight  of  sodium 
carbonate  and  one-fifth  that  amount  of  potassium  nitrate.  Dis- 
solve the  melt  in  a  small  porcelain  dish  with  as  little  water  as 
possible.  Clean  the  platinum  crucible  with  a  little  hydro- 
chloric acid;  acidulate  the  water  solution  of  the  melt  with  the 
same  acid.  Add  to  this  solution  the  cleanings  of  the  crucible 
and  also  10  c.c.  of  i  :  i  sulphuric  acid.  Evaporate  to  thick 
fumes.  Dissolve  the  residue  in  water.  When  the  iron  sul- 
phate is  dissolved,  wash  the  solution  into  a  10  by  i  inch  test 
tube  and  dilute  to  20  c.c.  Add  10  c.c.  of  cone,  nitric  acid  and 
finish  as  in  steels. 

For  higher  percentages  of  manganese  proceed  as  given  for 
high  manganese  in  soluble  ferro-titanium  except  that  the 


FERRO-TITANIUM  AND   TITANIUM   STEEL  53 

substance  is  gotten  into  solution  by  a  bisulphate  fusion  as 
given  under  the  determination  of  silicon  in  insoluble  ferro- 
titanium.  Transfer  the  sulphuric  acid  solution  of  the  melt  to 
a  liter  flask  and  precipitate  the  iron  and  titanium  with  zinc 
oxide.  Use  i  gram  of  sample  and  fuse  it  with  30  grams  of 
bisulphate. 

TITANIUM  STEELS. 

For  phosphorus,  manganese,  silicon,  aluminum  and  carbon 
proceed  as  in  plain  steels  if  the  titanium  is  present  to  the  extent 
of  a  few  tenths  of  a  per  cent. 

SULPHUR. 

Even  a  few  tenths  of  a  per  cent  of  titanium  lead  to  low  sulphur 
results  by  the  evolution  process.  For  example,  where  results 
showing  0.006  per  cent  by  evolution  were  obtained,  0.012  sul- 
phur was  gotten  by  the  ordinary  gravimetric  sulphur  method 
for  steels.  Again,  0.075  Per  cen^  sulphur  was  gotten  by  evo- 
lution in  a  titanium  experimental  ingot  when  the  gravimetric 
result  was  o.n  per  cent.  Use  either  the  gravimetric  process 
by  direct  solution,  or  fuse  2  grams  of  sample  with  20  grams  of 
sodium  carbonate  plus  4  grams  of  niter,  and  proceed  as  in  sul- 
phur in  high  silicon  ferro-vanadium,  filtering  out  the  sodium 
titanate  before  acidulating  with  HCL 

TITANIUM  IN  STEEL. 

Gravimetric. 

The  titanium  is  determined  gravimetrically  as  in  soluble 
ferro-titanium  except  that  four  or  five  grams  of  sample  should 
be  used. 

VOLUMETRIC. 

So  far  the  most  practical  way  is  the  well-known  color  method, 
using  hydrogen  peroxide.  The  author  proceeds  as  follows: 

Determine  gravimetrically  the  amount  of  titanium  in  a  ferro- 
titanium  containing  from  about  8  to  10  per  cent  of  titanium,  for 
use  as  a  color  standard. 


54  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

PLAIN  TITANIUM  STEEL. 

If  the  titanium  content  is  0.05  per  cent  or  over,  weigh  0.500 
gram  of  drillings  into  a  10  by  i  inch  tube.  Also  weigh  0.500 
gram  of  a  plain  carbon  steel  that  contains  no  titanium  by  the 
qualitative  test.  Add  to  the  latter  enough  of  the  standard 
ferro-titanium  to  bring  the  amount  of  titanium  present  in  this 
standard  mixture  to  within  about  0.05  per  cent  of  the  titanium 
content  of  the  test.  If  the  test  is  likely  to  be  about  0.15  per 
cent  Ti,  then  the  standard  should  either  be  about  o.io  per  cent 
Ti  or  0.20  per  cent  Ti.  The  nearer  the  standard  is  to  the  test, 
in  titanium  content,  the  better. 

Dissolve  the  drillings  in  10  c.c.  of  dilute  sulphuric  acid.* 
Add  5  c.c.  of  cone,  nitric  acid  and  boil  off  red  fumes.  Cool, 
rinse  the  standard  into  a  glass-stoppered  comparison  .tube  of 
about  15  to  1 6  mm.  outside  diameter  and  with  the  graduated 
part  about  38  cm.  long.  Add  to  the  solution  in  the  comparison 
tube  5  or  6  c.c.  of  the  peroxide  mixture  used  in  qualitative  Ti 
and  V  tests,  page  5.  Stopper  the  tube  and  mix  the  contents 
thoroughly.  Transfer  the  test  to  the  other  comparison  tube 
and  treat  it  in  like  manner.  If  there  is  a  great  difference  in 
color  between  standard  and  test,  results  will  only  be  roughly 
approximate  and  the  work  should  be  repeated,  preparing  a 
new  mixture  of  standard  ferro-titanium  and  plain  carbon  steel, 
to  imitate  the  test  within  the  0.05  limit  or  closer. 

The  following  actual  case  will  illustrate  calculations,  etc. : 

The  standard  mixture  consisted  of  8  mg.  of  8  per  cent  Ti 
ferro  plus  500  mg.  of  a  plain  carbon  steel  of  approximately  the 
same  carbon  content  as  the  sample  to  be  tested. 

The  test  matched  the  standard  at  38.3  c.c.  with  the  standard 
diluted  to  35  c.c.  Since  the  standard  contained  8  mg.  of  8  per 
cent  ferro-titanium,  its  color  was  due  to  the  presence  of  0.008  X 

*  Warm  in  boiling  water  before  adding  the  nitric  acid  until  the  solution  is  as 
free  as  possible  of  black  scum,  or  the  nitric  acid  will  dissolve  the  scum  to  a  brown 
color  which  will  augment  the  similar  color  due  to  the  titanium  and  peroxide. 
Select  a  plain  carbon  steel  as  near  the  carbon  content  of  the  titanium  steel  as  pos- 
sible to  reduce  the  interference  due  to  the  color  of  the  dissolved  carbon  to  a  mini- 
mum. See  page  60. 


FERRO-TITANIUM   AND   TITANIUM   STEEL  55 

0.08,  or  0.00064  gram,  of  metallic  titanium;   therefore  we  have 
the  proportion: 

Stand.  Vol.  Test  Vol. 

35  c.c.  :  38.3  c.c.  :  :  0.00064  :  X, 
or  38.3  X  0.00064  -=-  35  =  0.0007,  or  0.0007,  gram  of  titanium 
found.  0.0007  X  ioo  4-  0.5  =  0.14,  or  0.14  per  cent  titanium 
when  0.5  gram  is  taken  for  analysis.  The  gravimetric  result 
on  this  sample  was  0.158.  Another  sample  gave  0.134  per  cent 
by  color  and  0.140  per  cent  by  gravimetric  analysis. 

For  percentages  as  low  as  0.05  per  cent  and  under,  use  a 
gram  of  sample  and  proceed  accordingly,  preparing  standard 
mixtures  of  similar  percentage.  If  the  titanium  steel  also  con- 
tains not  over  one-half  per  cent  of  elements  that  color  acid  solu- 
tions, such  as  chromium  and  nickel,  the  amounts  of  the  latter 
present  in  the  test  should  be  determined  by  the  rapid  methods 
given  under  chromium  and  nickel  in  steel.  Add  to  the  stand- 
ard enough  shot  nickel  if  titanium  nickel  steel  is  being  tested, 
or  enough  potassium  dichromate  reduced  with  the  least  possible 
excess  of  sulphurous  acid  if  the  test  be  chrome-titanium  steel, 
to  exactly  imitate  the  sample  under  examination,  and  then 
proceed  as  usual. 

If  the  steel  contains  several  per  cents  of  chromium,*  fuse  2 
grams  with  a  mixture  of  20  grams  of  sodium  carbonate  and 
4  grams  of  niter.  Dissolve  the  melt  in  water.  Filter;  wash 
the  residue  on  the  filter  with  sodium  carbonate  water.  Roast 
the  pulp  out  and  fuse  again  as  before.  Dissolve  in  water, 
filter  and  wash.  Then  dissolve  the  residue  off  the  filter  with 
hot  hydrochloric  acid.  Wash  the  filter  free  of  iron  test.  Di- 
lute the  filtrate  and  washings  to  300  c.c.  and  pass  H2S  through 
it  until  all  platinum  has  been  precipitated.  Filter;  wash  the 
sulphides  with  H2S  water.  Evaporate  the  filtrate  and  wash- 
ings to  10  c.c.,  adding  one  gram  of  potassium  chlorate  before 
beginning  the  evaporation,  to  oxidize  the  iron  and  remove  H2S. 

Add  at  this  stage  30  c.c.  i  :  3  sulphuric  acid  and  evaporate 
to  heavy  fumes.  Dilute  with  water  and  then  finish  exactly  as  in 

*  Read  pages  62  and  63. 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


the   gravimetric    determination   of    titanium   in   plain   carbon 
steels. 

The  color  method  might  also  be  applied  to  such  steels  by  first 
removing  the  chromium  by  a  sodium  carbonate  and  niter  fusion 
as  just  given,  using  0.500  gram  of  sample.  The  sodium  titanate 
and  oxide  of  iron  could  then  be  spread,  filter  and  all,  in  a  small 
porcelain  dish  with  30  c.c.  i  :  i  hydrochloric  acid  and  heated 
for  30  minutes  or  more.  The  pulp  could  be  filtered  out  and 
washed;  30  c.c.  of  i  :  3  sulphuric  acid  added;  the  filtrate  and 
washings  evaporated  to  thick  fumes;  transferred  to  a  10  by  i 
inch  test  tube;  boiled  with  5  c.c.  cone,  nitric  acid  and  finished 
by  color.  For  a  standard  add  to  a  plain  chromium  steel  a 
suitable  amount  of  ferro-titanium  and  fuse  with  sodium  car- 
bonate and  niter,  putting  the  fusion,  etc.,  through  exactly  as  the 
test.  Use  this  for  the  color  standard.  Or  after  removal  of  the 
chromium  and  vanadium  by  a  double  fusion  with  sodium  carbon- 
ate and  niter,  then  fuse  the  iron  oxide  and  sodium  titanate  with 
potassium  bisulphate  and  finish  by  color,  or  gravimetrically. 

VANADIUM-TITANIUM  STEEL. 

Remove  the  vanadium  by  fusion  as  in  removal  of  chromium. 
Then  finish  gravimetrically  as  given  under  chromium  titanium 
steel,  or  convert  into  sulphate;  evaporate  to  10  c.c.;  wash  into 
a  10  by  i  inch  test  tube;  boil  with  5  c.c.  cone,  nitric  acid,  and 
finish  by  color.* 

QUALITATIVE  TEST  FOR  TITANIUM. 
Proceed    as   given   under   Qualitative   Test   for   Vanadium, 

page  5. 

ANALYSES. 


Insoluble  ferro-titanium. 

Soluble  ferro-titanium. 

Titanium  \  ™.  ^ 
rwi/u         C  "*Qi  

Per  cent. 
87.80 

0.85 
4.64 
0.52 
1.89 
0-055 

Titanium  

Per  cent. 

8.12 

0.58 
0.50 
86.92 
3-oo 

O.IO 

0.26 

uxiae         j 
Silica  SiO2 

Silicon  

Iron  Oxide  Fe2O3  
Sulphur  
Carbon 

Iron 

Aluminum  
Phosphorus  

Phosphorus 

Carbon 

*  Read  pages  62  to  63. 


FERRO-TITANIUM   AND   TITANIUM  STEEL  57 

SOLUBLE  FERRO-TITANIUM,  ELIMINATING  SOME  OF  THE 
FUSIONS. 

Titanium.  To  avoid  as  much  as  possible  the  making  of  fusions 
the  author  now  analyzes  f erro-titanium  of  the  soluble  type  as  fol- 
lows: Dissolve  i  gram  of  the  drillings,  or  powder,  in  a  liter 
boiling  flask  in  50  c.c.  of  i  :  3  sulphuric  acid,  heating  until 
action  is  over.  Carry  along  a  test  mixture  of  about  the  same 
proportions.  For  example,  30  mg.  of  metallic  aluminum  and 
0.850  gram  of  plain  carbon  steel  will  usually  come  within  close 
range;  or  still  better  a  f  erro-titanium  of  known  Al  and  Ti  con- 
tent can  be  analyzed  at  the  same  time  to  test  the  accuracy  of 
the  operator's  manipulations. 

Dilute  the  above  solution  to  300  c.c.  and  peroxidize  it  in  the 
manner  described  on  page  23,  beginning  at  the  point  where  one 
is  directed  to  "  dilute  to  about  300  c.c.,"  obtaining  filtrates  A 
and  B.  If  on  dissolving  the  iron  off  the  filter,  a  reddish,  rouge- 
like  portion  of  the  iron  resists  the  action  of  the  hot  i  :  i  HC1, 
remaining  as  a  red  stain  on  the  paper  pulp,  then  wash  the  latter 
with  water  until  the  washings  no  longer  give  a  test  with  silver 
nitrate;  burn  the  pulp  in  a  platinum  crucible  and  fuse  it  at  a 
bright  red  heat  with  the  sodium  carbonate  for  a  half  hour, 
using  enough  of  the  flux  to  equal  about  twenty  times  the  weight 
of  the  ash.  Dissolve  the  fusion  in  water;  acidulate  with  HC1, 
heating  with  enough  of  the  latter  to  dissolve  all  of  the  iron;  add 
this  solution  to  the  main  iron  solution  and  proceed  with  the 
second  peroxidation.  If  the  ferro  contains  as  much  as  10  per 
cent  Al,  a  third  solution,  peroxidation  and  filtration  are  neces- 
sary obtaining  a  third  filtrate  and  washings.  The  combined 
three  filtrates  will  contain  all  of  the  Al  in  the  f  erro-titanium. 
If  any  vanadium  be  present  it  will  all  be  in  the  same  place. 
All  of  the  iron  and  titanium  will  be  on  the  filter  from  the  third 
peroxidation  and  also  a  little  of  the  iron  will  remain  as  a  film 
on  the  inside  of  the  boiling  flask.  The  film  can  be  removed  by 
warming  in  the  flask  a  little  of  the  i  :  i  HC1  that  is  to  be  used  to 
dissolve  the  main  iron  and  titanium  off  the  filter.  Wash  the  fil- 


58  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

ter  and  pulp  from  the  final  solution  of  the  iron  and  titanium,  until 
it  tests  free  of  iron  with  KCNS  solution.  Retain  the  filter  and 
pulp  and  use  it  to  catch  the  first  precipitation  of  the  titanium, 
or  ignite  it  along  with  the  titanium  as  it  may  retain  some  of  the  Ti. 
The  final  solution  of  the  iron  and  titanium  in  HC1,  being 
now  free  of  Cr,  V  and  Al,  is  taken  to  heavy  fumes  with  50  c.c. 
of  i  :  3  sulphuric  acid;  cooled;  and  dissolved  to  a  clear  solution 
with  100  c.c.  of  water.  Filter  out  any  white  insoluble  matter; 
wash  it  free  of  iron  test  with  i  :  40  HoSO^  neutralize  the  filtrate 
and  washings  with  i  :  3  ammonia,  adding  the  same  until  a 
slight  turbidity  is  obtained  that  will  not  dissolve  on  continued 
stirring;  add  three  drops  of  i  :  3  H2SO4;  and  then  add  10  grams  of 
sodium  thiosulphate  (Na^&Oa).  Boil  thirty  minutes,  slowly; 
add  some  ashless  paper  pulp,  filter  and  wash  with  sulphurous 
acid  water  (500  c.c.  of  water  to  which  has  been  added  5  c.c.  of 
H2SO3);  after  fifteen  washings,  begin  to  test  the  wash  water 
for  iron  and  continue  the  washing  until  no  blue  test  for  iron  is 
obtained  with  potassium  ferricyanide.  Dry  the  filter  and  pulp, 
and  burn  it  at  a  low  heat  until  the  paper  is  all  gone;  if  the  residue 
in  the  crucible  is  not  pure  white  or  slightly  yellow,  but  has  a 
reddish  tint,  it  still  contains  iron  and  must  be  fused  with  10 
grams  of  acid  potassium  sulphate  (KHSO4).  This  fusion  is 
very  satisfactory  but  must  not  be  hurried.  Place  the  10  grams 
of  KHS04  in  the  crucible  on  top  of  the  residue;  cover  the  cru- 
cible and  warm  it  over  an  argand  burner,  cautiously;  lift  up 
the  lid  occasionally  to  make  sure  that  the  heat  is  not  high 
enough  to  cause  the  flux  to  spatter  against  the  lid;  continue 
this  low  heat  for  a  half  hour  or  more  until,  on  increasing  the 
heat  a  little,  there  arises  a  slight  fume  of  sulphuric  anhydride; 
continue  to  increase  the  heat  slightly  until,  finally,  a  bright 
red  heat  has  been  attained  without  any  boiling  action.  The 
melt  should  be  transparent  and  contain  no  undissolved  dark 
particles;  it  should  be  as  clear  as  water,  when  red  hot,  except 
for  white  flakes  of  silica  if  the  latter  be  present.  Place  the 
melt,  crucible  and  all,  in  a  No.  5  porcelain  dish  together  with 
50  c.c.  of  i  :  3  H2S04  and  an  equal  amount  of  water,  and  heat 


FERRO-TITANIUM   AND  TITANIUM   STEEL  59 

until  the  melt  is  all  dissolved  out  to  a  clear  solution  with  per- 
haps some  white  particles  of  silica  floating  in  it.  Do  not  filter, 
but  neutralize  the  acid  until  a  faint  white  cloudiness  is  obtained 
that  will  not  dissolve  on  persistent  stirring;  reprecipitate  the 
titanium  as  before  by  boiling  with  10  grams  of  the  thiosulphate; 
filter  and  wash  the  precipitated  titanium  as  before;  dry  it; 
ignite  and  weigh  it  as  titanic  oxide  plus  some  Si02;  remove 
the  latter  as  described  on  page  44. 

Aluminum.  This  element  can  be  obtained  from  the  combined 
filtrates  from  the  peroxidations,  page  57,  by  acidulating  the  same 
with  HC1  and  precipitating  the  Al  with  a  slight  excess  of  ammonia 
after  boiling  off  the  carbon  dioxide.  This  Al  should  be  redis- 
solved  in  HC1  and  reprecipitated  to  free  it  from  sodium  salt. 
It  is  then  ignited  and  weighed  as  described  on  page  46,  except 
that  any  phosphorus  that  may  be  found  in  the  precipitate 
cannot  be  taken  as  the  total  P  in  the  ferro  since  by  dissolving 
the  latter  in  sulphuric  acid  much  of  the  P  is  lost  as  phosphine. 
Deduct  from  the  Al  found,  the  excess  of  Al  gotten  in  the  test 
mixture,  if  any,  over  and  above  the  Al  put  in  the  test  mixture. 

Phosphorus  and  Sulphur.  These  elements  can  be  best  deter- 
mined as  given  on  page  45,  but  if  it  is  desired  to  avoid  niter 
and  carbonate  fusions  in  platinum,  then  fuse  i  gram  of  the 
finely  powdered  sample,  or  thin  drillings,  in  an  iron  crucible 
with  8  grams  of  sodium  peroxide;  dissolve  the  fusion  out  in 
water  in  the  same  manner  as  described  for  chrome  ore  on  page 
140;  remove  the  crucible  and  acidulate  the  water  solution  with 
HC1;  heat  until  the  iron  is  all  dissolved;  precipitate  the  iron 
out  with  ammonia;  dissolve  it  off  the  filter  with  1.20  nitric  acid 
and  finish  for  phosphorus  by  boiling  with  a  slight  excess  of 
KMn04,  clearing  with  ferrous  sulphate  and  precipitating  with 
molybdate.  Run  blanks  on  all  operations  for  phosphorus. 

Iron.  The  iron  can  be  obtained  as  given  on  page  47,  or  0.500 
gram  of  the  sample  can  be  decomposed  as  described  for  tita- 
nium on  page  60  up  to  the  point  where  all  is  in  solution  and 
ready  for  the  second  peroxidation ;  evaporate  this  iron- titanium 
solution  to  250  c.c.;  reduce  it  with  stannous  chloride;  take  up  the 


60  CHEMICAL  ANALYSIS  OF  SPECIAL   STEELS 

excess  of  the  latter  with  mercuric  chloride;  and  titrate  the  iron 
with  a  standard  solution  of  potassium  dichromate  as  in  iron  ore. 
Insoluble  F err o-T Itanium.  Instead  of  decomposing  this  type 
of  ferro-titanium  by  the  bisulphate  fusion  as  outlined  on  page 
51,  i  gram  of  the  finely  ground  sample  can  be  fused  in  a  plat- 
inum crucible  with  a  mixture  of  10  grams  of  sodium  carbonate 
and  2  grams  of  niter.  The  melt  is  dissolved  out  in  a  platinum 
dish  with  water  and  is  then  transferred  to  a  casserole  before  acidu- 
lating the  water  solution.  An  excess  of  HC1  is  then  added  to 
the  water  solution.  The  crucible  is  rinsed  off  with  water  into 
the  casserole;  cleaned  by  warming  in  it  a  little  HC1.  The 
cleanings  are  added  to  the  acidulated  solution  in  the  casserole 
which  is  heated  with  a  cover  on  it  until  all  action  is  over.  The 
contents  of  the  casserole  are  evaporated  twice  to  dryness;  dis- 
solved in  HC1;  heated  with  100  c.c.  of  water;  filtered  and  washed 
after  each  evaporation;  the  combined  filters  from  the  two 
evaporations  will  contain  all  of  the  silica  and  a  little  of  the 
titanium;  these  are  ashed  carefully;  weighed  and  evaporated 
with  HFL  and  5  drops  of  cone.  H^SO^  and  the  silica  obtained 
from  the  loss  of  weight.  The  residue  remaining  in  the  crucible 
is  fused  with  20  times  its  weight  of  Na2COs;  dissolved  in  HC1 
and  added  to  the  filtrate  from  the  second  evaporation  to  dry- 
ness  to  remove  silicon.  This  filtrate  and  washings  now  contain 
all  of  the  Ti,  P,  Al,  Fe,  and  S  in  the  sample.  The  filtrate  can  be 
diluted  to  a  definite  volume  and  one-half  reduced  with  stannous 
chloride  and  titrated  with  standard  dichromate  solution  for  iron, 
paying  no  attention  to  the  Ti  present  as  Ti  has  no  effect  on 
the  dichromate.  The  other  half  can  be  then  peroxidized  as 
given  on  pages  57  and  58  to  obtain  the  other  elements.  This 
scheme  obtains  the  iron  avoiding  the  reduction  with  H^S. 

THE  DETERMINATION  OF  VERY  Low  PERCENTAGES  OF 
TITANIUM  IN  STEEL. 

By  the  scheme  given  on  page  54,  a  little  scum  of  carbon  remains 
after  the  solution  in  sulphuric  acid  and  is  dissolved  subsequently 
by  the  nitric  acid,  imparting  a  slight  brown  color  to  the  solu- 


FERRO-TITANIUM  AND   TITANIUM   STEEL  6 1 

tion.  Hence  it  is,  at  all  times,  advisable  when  preparing  a 
standard  mixture  to  select  a  titanium-free  steel  as  near  to  the 
carbon  content  of  the  sample  to  be  tested  as  possible.  In 
this  way  about  the  same  amount  of  color  due  to  the  carbon  may 
be  in  both  standard  and  test.  It  is  necessary  to  eliminate 
this  color,  entirely,  when  one  is  to  determine  the  titanium  in  a 
sample  containing  only  o.oi  to  0.05  per  cent  Ti.  ». 

Dissolve  4  grams  of  drillings  in  50  c.c.  of  i  13  sulphuric  acid 
and  evaporate  to  fumes;  dissolve  by  heating  with  100  c.c.  of 
water;  filter  when  all  iron  is  dissolved;  the  residue  on  the 
filter,  after  washing  it  free  of  iron  test  with  i  :  40  H2S04,  is 
ignited  in  a  platinum  crucible;  evaporated  with  HF1  and  a  few 
drops  of  sulphuric  acid.  Hold  this  residue  in  the  crucible  and 
call  it  B.  Add  ammonia  to  the  filtrate  and  washings  from  B 
until  a  slight  turbidity  is  obtained  that  will  not  dissolve  even 
with  persistent  stirring;  then  add  10  grams  of  sodium  thiosul- 
phate  and  boil  for  30  minutes;  filter  out  the  precipitate  and 
wash  it  with  sulphurous  acid  water  and  burn  it  with  B.  Fuse 
the  total  ash  with  20  times  its  weight  of  KHSC^;  dissolve  the 
fusion  in  water;  add  to  the  water  solution  100  c.c.  of  1.20  nitric 
acid;  heat;  cool;  wash  into  a  250  c.c.  flask;  dilute  to  the 
mark;  mix  well  and  compare  with  a  standard  mixture  consist- 
ing of  5  mgs.  of  8.2  percent  ferro-titanium  and  4  grams  of  steel, 
free  of  titanium,  which  has  been  put  through  all  of  the  above 
operations  and  also  diluted  to  the  mark  in  a  250  c.c.  volumetric 
flask.  Suppose  that  25  c.c.  of  the  test  solution  is  compared 
with  25  c.c.  of  the  standard  mixture  as  given  on  page  54  and 
that  the  standard  matched  the  test  with  the  former  at  54  c.c. 
and  the  latter  at  32  c.c.  25  c.c.  of  the  standard  equals  25/250 
of  5  mgs.  X  0.082,  or  0.041  mg.  Ti;  therefore  54  :  32  :  :  0.041 
mg.  :  x  equals  0.024  mg.  Ti  in  500  mgs.  of  sample.  0.024 
divided  by  500  X  100  equals  0.0048,  or  per  cent  Ti  in  the  sam- 
ple equals  0.0048  per  cent. 


62  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


THE  DETERMINATION  OF  TITANIUM  IN  NICKEL  STEEL. 

Suppose  it  is  required  to  obtain  the  titanium  content  of  a 
steel  containing  3.60  per  cent  Ni  :  Dissolve  5  grams  of  the 
sample,  as  on  page  54,  using  75  c.c.  of  i  :  3  sulphuric  acid  for 
the  solution,  heating  in  boiling  water  for  one  hour  to  eliminate 
as  much  as  possible  the  carbon  before  adding  the  25  c.c.  of 
cone,  nitric  acid  to  accomplish  the  oxidation  of  the  iron  and 
dissolve  the  titanium.  For  a  standard  mixture  dissolve  and 
oxidize  5  grams  of  plain  steel  to  which  enough  nickel  ammonium 
sulphate  has  been  added  to  equal  3.60  per  cent  Ni  in  5  grams, 
.and  also  5  mgs.  of  8.20  per  cent  Ti  ferro- titanium.  Dilute  the 
cooled  solutions  of  the  standard  and  test  to  the  mark  in  250  c.c. 
volumetric  flasks;  mix  and  note  if  the  two  solutions  are  about 
the  same  shade  of  brown.  If  the  standard  solution  is  distinctly 
browner  prepare  a  new  standard  using  a  lower  carbon  plain 
carbon  steel,  adding  the  nickel  sulphate  and  5  mgs.  standard 
ferro- titanium.  If  now  there  is  only  a  slight  difference  in  the 
color  of  the  solutions  due  to  dissolved  carbon  proceed  with  the 
comparisons  in  the  manner  described  on  page  54  using  25  c.c. 
from  each  flask.  This  method  was  used  on  a  steel  that  con- 
tained 0.008  per  cent  Ti.  There  would  seem  to  be  no  objec- 
tion to  using  the  first  method  given  for  very  low  percentage 
titanium  steels  on  this  almost  equally  low  titanium-nickel  steel, 
in  case  the  operator  cannot  eliminate  the  interference  of  carbon 
by  selection.  (See  page  60.) 


THE  DETERMINATION  OF  TITANIUM  IN  CHROMIUM-VANA- 
DIUM-NICKEL-TITANIUM-TUNGSTEN STEEL. 

Owing  to  the  interference  of  the  vanadium  and  the  chromium, 
the  latter  must  be  removed.  This  can  be  best  done  by  peroxi- 
dizing  the  solution  of  the  sample  and  standard  mixtures  in  the 
same  manner  as  described  on  pages  57  to  58.  If  the  chromium 
is  considerable  it  will  require  three  peroxidations  at  least  to 


FERRO-TITANIUM  AND   TITANIUM   STEEL  63 

• 
remove  the  chromium   and  vanadium.     The   redissolving  and 

reperoxidizing  must  be  continued  until  the  filtrate  from  the 
iron  and  titanium  is  no  longer  colored  yellow.  The  steel  and 
standard  mixtures  are  dissolved  in  50  c.c.  of  i  :  3  sulphuric 
acid;  0.500  gram  of  sample  is  taken  for  analysis.  A  chroniium- 
tungsten-vanadium  steel  containing  no  nickel  or  titanium  was 
used  as  a  basis  of  a  standard,  and  to  it  was  added  35  mgs.  of 
nickel  ammonium  sulphate  and  5  mgs.  of  8.20  per  cent  (Ti) 
ferro-titanium.  After  the  chromium  color  has  been  removed 
by  several  peroxidations  from  the  standard  and  test,  the  iron 
and  titanium  are  dissolved  off  the  filters  with  50  c.c.  of  hot 
i  :  i  HC1 ;  the  filter  is  washed  free  of  iron ;  the  filtrate  and  wash- 
ings will  contain  all  of  the  titanium  and  iron  except  a  slight 
amount  that  may  still  remain  on  the  filter,  which  is  ashed  and 
fused  with  one  gram  of  sodium  carbonate;  the  fusion  is  dis- 
solved in  20  c.c.  of  i  :  i  HC1  and  added  to  the  main  solution  of 
the  iron  and  titanium.  Evaporate  this  latter  solution  to  5  or 
10  c.c.;  add  100  c.c.  of  strong  nitric  acid;  heat  with  the  cover 
on  until  all  spraying  is  over  and  then  evaporate  to  5  c.c.;  add 
10  c.c.  of  water  and  filter  into  the  comparison  tube  washing 
with  1.20  nitric  acid;  add  10  c.c.  of  peroxide  solution  and  com- 
pare. Example:  Test  matched  the  standard  mixture  as  follows: 
76.7  c.c.  test  equal  91.2  c.c.  of  standard;  therefore  since  the 
standard  contained  0.41  mg.  Ti,  76.7  :  91.2  ::  x  :  0.41  mg.  Ti,  or 
76.7  times  0.41  mg.  Ti  divided  by  91.2  divided  by  500  multi- 
plied by  100  equals  0.068  per  cent  Ti.  A  duplicate  analysis 
on  this  steel  gave  0.070  per  cent  Ti,  using  0.600  gram  of  sample. 
In  the  case  of  a  similar  steel  that  contained  0.80  per  cent  Ti, 
the  nitric  acid  solutions  containing  the  iron  and  titanium,  freed 
as  above  from  the  V  and  Cr,  were  diluted  to  250  c.c.  and  50  c.c. 
were  taken  from  the  standard  and  test  for  the  comparisons.  0.81 
per  cent  Ti  was  obtained  and  a  check  of  0.78  per  cent  Ti.  No 
attention  is  paid  to  the  tungsten  as  it  is  removed  along  with  the 
Cr  and  V. 


64 


CHEMICAL  ANALYSIS  OF   SPECIAL   STEELS 


CALCULATIONS. 

70  mg.  of  8.2  per  cent  Ti  ferro-titanium  were  used  in  the  standard  mixture; 
61.5  c.c.  of  standard  equal  78  c.c.  of  test.  One-fifth  of  70  mg.  times  0.082  equals 
1.148  mg.  Ti.  Therefore  61.5  :  78  : :  1.148:  x\  x  equals  1.456  mg.  Ti.  Now 
0.9  gram  was  taken  in  this  case  for  the  analysis  and  one-fifth  or  0.18  gram  of 
the  test  was  used  in  the  comparison;  hence  0.00145  gram  X  100  divided  by  0.18 
equals  0.809  Per  cent  Ti. 

SOME  FURTHER  ANALYSES  OF  FERRO-TITANIUM. 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

Carbon  

Per  cent. 
7.OO 

Per  cent. 
I  .OS 

Per  cent. 
0.04 

Per  cent. 
3  .60 

Per  cent. 
1.85 

Manganese  

0.28 

O.4O 

O.  30 

o.  19 

o.  15 

Silicon 

I   08 

o  64 

2      SI 

O  42 

14.    QO 

Titanium 

7    3O 

8  40 

2O  44 

2Q    17 

6  is 

Aluminum. 

O  42 

2    Q3 

3    IO 

o  87 

2    2S 

Iron 

84.20 

86.53 

73    17 

56.78 

74.60 

Chromium        .           .    . 

O.  S2 

Phosphorus  

o.  15 

Chromium.  The  chromium  was  obtained  in  the  above  No.  3 
as  in  a  steel,  no  attention  being  paid  to  the  presence  of  titanium. 

Analysis  of  Basic  Slag  Containing  Titanium. 

Silica.  Dissolve  i  gram  of  the  finely  ground  slag,  after  first 
stirring  it  into  a  thin,  smooth  paste  with  a  very  little  water,  in 
a  No.  5  porcelain  dish  in  50  c.c.  of  cone.  HC1.  Warm  until 
solution  is  practically  complete,  evaporate  to  dryness  and  heat 
until  very  little  acid  can  be  detected  when  hot.  Dissolve  again 
in  30  c.c.  of  cone.  HCL;  add  100  c.c.  of  water;  filter;  wash  free 
of  iron  test.  Burn  in  a  weighed  platinum  crucible;  add  a 
large  excess  of  HaSCX,  about  2  c.c.  to  prevent  loss  of  Ti  as 
fluoride  and  remove  the  silica  with  15  c.c.  of  HF1;  calculate 
the  loss  of  weight  to  silica.  For  extreme  accuracy  the  solution 
of  the  slag  should  be  evaporated  twice  to  dryness  with  HC1, 
filtering  after  each  evaporation  and  solution  in  HC1  and  water. 

Oxide  of  Iron.  Dissolve  i  gram  of  the  slag,  as  for  the  silica,  in 
a  600  c.c.  beaker  and  dilute  the  solution  to  300  c.c.;  heat  to 


FERRO- TITANIUM   AND    TITANIUM    STEEL  65 

boiling;  reduce  with  stannous  chloride  without  separating  the 
titanium;  cool;  add  an  excess  of  mercuric  chloride  solution  and 
titrate  with  N/2O  potassium  dichromate  as  in  iron  ores. 

Titanium  Oxide.  Dissolve  i  gram,  as  for  silica,  in  a  liter  boil- 
ing flask  and  dilute  to  300  c.c.;  make  two  peroxidations  as  de- 
scribed on  page  57,  obtaining  the  titanium  and  iron  on  the  filter 
and  the  alumina  in  the  combined  nitrates  and  washings  from  the 
two  peroxidations. 

Oxides  of  Manganese,  Calcium  and  Magnesium.  Dissolve 
i  gram  in  50  c.c.  of  cone.  HC1  in  a  600  c.c.  beaker  and  make 
two  basic  separations,  as  directed  for  the  separation  of  iron 
from  manganese  on  page  188,  beginning  at  the  point  where  the 
nitrate  and  washings  are  diluted  to  300  c.c.  The  combined 
nitrates  from  the  two  basic  acetate  separations  contain  all 
the  Ca,  Mg  and  Mn  in  the  slag.  Acidulate  the  combined 
nitrates  with  HC1  and  evaporate  them,  if  necessary,  to  400  c.c. 
and  make  the  same  slightly  but  distinctly  ammoniacal.  Then 
add  slowly  a  water  solution  of  potassium  ferricyanide;  use 
the  c.p  salt  of  a  clear  resinous  red  color  and  free  of  the  suggestion 
of  bluish  color,  as  ferricyanide  containing  blue  material  is  partly 
decomposed  as  follows:  Fe(CN)3  -  3  KCN  =  Fe(CN)2  +  CN  + 
3  KCN,  and  will  not  precipitate  the  true  manganese  ferricyanide 
but  a  mixture  of  the  latter  and  cyanide  of  iron.  Dissolve  3.75 
grams  of  the  potassium  ferricyanide  in  water  and  dilute  to  i  liter, 
i  c.c.  of  this  solution  will  precipitate  about  0.001075  gram  of 
manganese.  See  page  200  for  the  equation  explaining  the 
manner  in  which  the  manganese  is  precipitated  from  an  ammo- 
niacal solution  by  potassium  ferricyanide.  Add  a  slight  excess 
of  the  precipitant  and  allow  the  solution  to  stand  a  half  hour 
before  filtering.  Mix  some  paper  pulp  with  the  precipitate, 
filter  it,  and  wash  it  with  a  solution  of  5  grams  of  ammonium 
nitrate  dissolved  in  500  c.c.  of  water  made  ammoniacal  with 
5  c.c.  of  strong  ammonia.  In  order  to  secure  a  rapidly  subsid- 
ing precipitate  it  is  best  to  make  the  manganese  solution,  at 
first,  just  ammoniacal  enough  to  turn  a  small  piece  of  red  lit- 
mus paper  floating  in  it  blue;  then  add  5  c.c.  of  i  :  i  ammonia 


66  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

water  in  excess.  After  washing  the  manganese  ferricyanide 
as  described  until  i  c.c.  of  the  washings  acidulated  with  nitric 
acid  no  longer  give  a  chlorine  test  with  silver  nitrate,  it  is  burned 
at  a  low  red  heat  until  free  of  carbon  of  the  filter  paper;  it  then 
consists  of  a  mixture  of  oxides  of  manganese  and  iron  which 
can  be  analyzed  for  manganese  as  usual.  This  mixture  of 
oxides  of  manganese  and  iron  seems  to  be  of  fairly  constant 
percentage  of  manganese  if  always  burned  off  at  definite  tem- 
perature. The  author  is  not  yet  prepared  to  recommend 
weighing  the  mixture  of  oxides  as  a  gravimetric  method  for 
manganese.  He  made  many  experiments  with  this  in  view 
and  obtained  some  promising  results.  Where  large  amounts 
of  manganese  are  precipitated  in  this  way  in  the  presence  of 
lime,  it  is  advisable  to  dissolve  the  mixture  of  oxides  in  20 
c.c.  of  cone.  HC1  and  make  a  basic  acetate  separation  of  the 
iron;  the  manganese  in  the  filtrate  and  washings  from  the 
iron  acetate  is  again  precipitated  as  before  with  ferricyanide 
and  the  filtrate  and  washings  from  the  manganese  are  combined 
with  the  filtrate  and  washings  from  the  original  ferricyanide 
precipitation  of  the  manganese.  In  this  way  the  possibility  of 
any  lime  being  carried  out  with  the  manganese  ferricyanide  is 
obviated.  This  second  precipitate  of  manganese  ferricyanide  is 
burned  off  with  the  iron  from  which  it  has  just  been  separated, 
otherwise  two  basic  acetate  separations  would  have  to  be 
made  at  this  point  instead  of  one.  The  total  ash  contains  all 
of  the  manganese  freed  from  the  lime  and  magnesia.  The 
manganese  can  now  be  determined  as  on  page  188  or  under 
" Second  Portion,"  page  192. 

Lime  and  Magnesia.  The  combined  filtrates  from  the  two 
manganese  ferricyanide  precipitations  are  treated  with  100  c.c. 
of  cone,  nitric  acid  and  evaporated  to  dryness.  This  acid 
should  be  added  to  the  solution  before  the  evaporation  begins, 
to  prevent,  as  far  as  possible,  the  formation  of  the  blue  cyanides. 
When  the  evaporating  solution  reaches  a  certain  degree  of  con- 
centration it  should  be  watched  as  spraying  may  begin,  and 
at  this  stage  the  casserole  should  be  covered  until  this  action 


FERRO-TITANIUM    AND   TITANIUM  STEEL 


67 


is  over;  the  dover  is  then  removed  and  the  evaporation  con- 
tinued to  dry  ness.  The  residue  in  the  casserole  is  taken  up 
with  100  c.c.  of  HC1  and  concentrated  to  20  c.c.  after  the  action 
between  the  acid  and  the  salts  is  over.  Add  100  c.c.  of  water; 
and  precipitate  the  iron  with  ammonia;  filter;  wash  with  water 
until  the  washings  are  free  of  chloride  test  obtaining  nitrate 
(A).  Redissolve  the  iron  hydrate;  and  precipitate  it  again; 
filter;  wash;  and  combine  the  filtrate  and  washings  with  (A). 
The  combined  filtrates  and  washings  are  made  faintly  ammo- 
niacal  and  the  calcium  is  precipitated  with  ammonium  oxalate 
as  in  the  analysis  of  limestone.  The  oxalate  is  filtered,  washed, 
and  reprecipitated.  The  two  filtrates  from  the  oxalate  are  com- 
bined and  the  magnesium  is  precipitated  as  given  on  page  334. 
Phosphorus.  Weigh  0.500  gram  of  the  slag  into  a  porcelain 
dish  and  with  it  an  equal  amount  of  potassium  chlorate; 
moisten  to  a  thin  paste  with  water  and  then  pour  in  50  c.c.  of 
cone.  HC1.  Heat  until  all  is  in  solution  except  the  silicic  acid, 
remove  the  cover  and  evaporate  to  dryness  but  not  at  a  baking 
heat.  Redissolve  with  30  c.c.  of  cone.  HC1;  and  add  50  c.c. 
of  water;  filter;  wash;  convert  to  nitrates  by  evaporating 
twice  to  20  c.c.  with  50  c.c.  of  cone,  nitric  acid;  boil  with  a 
slight  excess  of  KMnCX  and  finish  as  for  phosphorus  in  steel. 

THE  ANALYSIS  FOUND. 


SiO2 

Per  cent. 
10   4=J 

MgO 

<c  80 

FeO 

6  7«; 

MnO 

900 

AI»O,.. 

I  .CX 

TiO2.  . 

*  61 

CaO  

47.66 

P2O6 

4-3Q 

CHAPTER  IV. 

PART  I. 
ANALYSIS  OF  TUNGSTEN  POWDER. 

FUSE  0.6  gram  of  the  powder  with  a  mixture  of  10  grams  of 
carbonate  of  soda  well  ground  in  a  mortar  with  2  grams  of  potas- 
sium nitrate.  A  complete  fusion  is  obtained  in  twenty  minutes. 
The  melt  is  dissolved  with  water  in  a  platinum  dish.  It  is 
transferred  to  a  300  c.c.  casserole  and  acidulated  with  hydro- 
chloric acid  —  keeping  the  dish  covered  during  acidulation. 
The  solution  is  heated  for  a  half  hour  with  cover  on,  or  until 
all  danger  of  loss  by  spraying  is  over.  The  cover  is  removed 
and  the  acidulated  fusion  is  evaporated  to  dryness.  10  c.c.  of 
i  :  i  hydrochloric  acid  are  then  added  and  the  contents  warmed 
until  iron  is  dissolved.  200  c.c.  of  water  are  next  put  into  the 
dish,  and  the  solution  is  heated  for  thirty  minutes  to  dissolve 
all  sodium  salts. 

The  precipitated  tungstic  acid  is  filtered  out  and  washed  free 
from  iron  test  with  very  dilute  hydrochloric  acid.  It  is  washed 
twenty  more  times  to  insure  removal  of  salts.  The  filtrate 
and  washings  are  again  evaporated  to  dryness,  dissolved,  filtered, 
and  washed  as  before.  The  second  filtrate  and  washings  are 
treated  with  a  hydrochloric  acid  solution  of  cinchonine  to  remove 
the  last  traces  of  tungstic  acid.  (See  page  109.) 

The  three  portions  of  the  tungsten  are  burned  off  at  a  low 
red  heat  until  bright  yellow.  This  yellow  residue  is  weighed 
and  fused  with  10  grams  of  potassium  bisulphate  until  the 
fusion  is  clear  and  transparent.*  The  melt  is  cooled  and  dis- 
solved in  a  platinum  or  porcelain  dish  in  a  water  solution  of 
15  grams  of  ammonium  carbonate,  warming  gently  to  hasten 

*  Read  page  58. 
68 


ANALYSIS   OF   TUNGSTEN   POWDER  69 

solution.  Remove  the  dish  from  the  heater  as  soon  as  the 
fusion  is  dissolved. 

The  small  residue  of  iron  and  silica  is  filtered  out  and  washed 
free  of  sulphate  test  with  ammonium  carbonate  solution.  This 
residue  is  ignited  and  weighed,  and  its  weight  deducted  from 
the  weight  of  the  yellow  oxide.  The  remainder  is  multiplied 
by  79.31,  and  divided  by  the  weight  of  sample  taken  for  analysis 
to  obtain  the  percentage  of  tungsten.  If  the  silica  residue  is 
large  or  has  yellowish  tints,  fuse  it  again.  It  may  contain 
tungsten.  Unless  it  is  fused  again,  dissolved  in  ammonium 
carbonate  and  washed  and  weighed,  the  tungsten  result  will 
be  too  low.  This  last  weight  will  be  the  correct  deduction  for 
silica,  iron  oxide,  etc.  If  the  first  fusion  and  preceding  opera- 
tions have  been  conducted  as  given,  the  silica  will  be  practically 
pure  white,  containing  only  traces  of  other  oxides. 

When  the  first  bisulphate  fusion  is  being  dissolved  in  ammo- 
nium carbonate  water,  as  stated,  it  should  be  only  warmed  to 
start  the  action,  and  the  heat  should  be  shut  off  the  moment 
the  bisulphate  is  in  solution,  otherwise  tungsten  may  be  found 
with  the  silica. 

Rapid  Method  for  Tungsten.  Weigh  i  gram  of  metal  into 
a  platinum  dish.  Add  10  c.c.  of  pure  hydrofluoric  acid.  Cover 
with  a  lid.  Warm  in  a  good  draught.  Remove  from  fire. 
Add  three  or  four  drops  of  cone,  nitric  acid.  Violent  action 
occurs  at  this  point.  Continue  to  add  nitric  acid  a  drop  at  a 
time  until  further  additions  of  acid  produce  no  action.  This 
will  take,  in  all,  about  5  c.c.  of  cone,  nitric  acid.  Remove  the 
lid,  rinsing  off  its  surface,  permitting  the  washings  to  flow  into 
it.  Add  10  c.c.  cone,  sulphuric  acid.  Evaporate  to  thick 
fumes  of  SOs.  Cool,  moisten  with  10  c.c.  of  cone,  hydro- 
chloric acid.  Add  10  c.c.  of  water,  transfer  the  contents  of  the 
dish  to  a  600  c.c.  casserole,  and  heat  to  boiling  with  constant 
stirring  to  prevent  bumping.  Cool.  Filter.  Wash  with  i  :  10 

*  Add  cinchonine  to  the  filtrate  and  washings  and,  after  several  hours,  filter  off 
any  tungstate  that  may  have  formed,  and  add  it  to  the  main  tungstic  acid  before 
it  is  fused  with  KHSO4. 


70  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

hydrochloric  acid  until  free  of  iron  test.*  Ignite  and  weigh  the 
tungstic  acid  as  trioxide.  Fuse  the  latter  with  potassium  bi- 
sulphate  and  finish  as  in  the  first  method.  This  rapid  scheme  is  a 
modification  of  Arnold  and  Ibbotson's  method,  and  usually  gives 
results  one-  or  two- tenths  of  one  per  cent  lower  than  the  longer 
method,  which  must  be  resorted  to  for  complete  analysis  of  the 
powders.  (See  .Arnold  and  Ibbotson's  Steel  Works  Analysis,  1 907 .) 

Iron,  Phosphorus  and  Sulphur*  If  these  elements  are  asked 
for,  i  gram  of  sample  should  be  fused  with  20  grams  of  sodium 
carbonate  and  4  grams  of  potassium  nitrate.  Then  proceed 
exactly  as  for  tungsten  until  just  before  adding  the  cinchonine. 
(A)  Divide  the  filtrate  and  washings,  instead  of  adding  the 
cinchonine,  into  two  equal  parts.  To  one  portion  add  the 
cinchonine;  the  small  precipitate  is  burned  off  and  weighed  by 
itself.  Evaporate  it  with  a  little  hydrofluoric  and  sulphuric 
acids.  Ignite  it  and  multiply  its  weight  by  two.  Add  this 
amount  to  the  tungsten  trioxide  found  by  the  two  evapora- 
tions to  dryness.  Calculate  this  total  trioxide  to  percentage 
on  the  basis  of  i  gram  taken  for  analysis.  (B)  To  the  other 
portion  of  the  divided  filtrate  and  washings  obtained  after  the 
second  evaporation  add  a  slight  excess  of  ammonia.  Heat, 
filter,  and  wash  with  hot  water.  Ignite  this  precipitate,  but 
do  not  weigh  it,  as  it  is  almost  sure  to  contain  nearly  all  of  the 
tungsten  that  remained  in  this  portion  of  the  divided  filtrates. 
Dissolve  it  with  hydrochloric  acid;  evaporate  off  excess  of 
acid;  dilute  with  water;  filter  out  any  tungstic  acid  that  may 
separate,  washing  the  latter  free  from  iron  with  i  :  20  hydro- 
chloric acid.  The  filtrate  and  washings  are  evaporated  to  thick 
fumes  with  60  c.c.  i  13  sulphuric  acid  and  reduced  with  zinc  and 
titrated  with  the  same  permanganate  standard  that  is  used  for 
iron  oxide  determinations  in  graphite  (seepage  338).  Calculate 
the  iron  found  as  metal,  and  multiply  the  result  by  two  to 
obtain  the  percentage  on  the  basis  of  i  gram. 

Phosphorus.  The  author  has  found  that  the  practice  of 
decomposing  tungsten-containing  materials  by  fusing  them 

*  Read  page  73. 


ANALYSIS   OF  TUNGSTEN   POWDER  71 

with  a  mixture  of  sodium  carbonate  and  potassium  nitrate,  leach- 
ing out  the  fusion,  acidulating  with  hydrochloric  acid,  removing 
the  tungstic  acid  by  several  evaporations  to  dryness,  and  then  us- 
ing the  nitrate  and  washings  from  the  tungstic  acid  for  the  deter- 
mination of  the  phosphorus,  gives  far  less  than  the  actual  per  cent. 

The  method  that  he  now  uses  together  with  the  proof  of  the 
accuracy  of  the  same,  he  first  published  in  the  Journal  of  Ind. 
and  Eng.  Chem.,  Vol.  5,  No.  4.  The  full  description  of  his 
method  can  be  found  on  page  82. 

Sulphur.  The  first  filtrate  and  washings  obtained  from  the 
ammonia  precipitation  of  the  iron  are  made  slightly  acid  with 
hydrochloric  acid.  Barium  chloride  is  added,  and  the  sulphur  is 
finished  as  in  gravimetric  sulphur  in  steels.  Multiply  the  result 
by  2  to  bring  it  to  i  gram  taken  for  analysis.  (Read  page  73.) 

When  sulphur  is  determined,  a  blank  should  be  run,  begin- 
ning with  the  melting  of  the  same  flux.  The  BaS04  obtained 
is  deducted  before  calculating  the  per  cent  of  sulphur. 

Carbon.  Burn  3  grams  with  4  grams  of  red  lead,  deducting 
the  blank  due  to  the  lead. 

Manganese.  Fuse  o.ioo  gram  with  2  grams  sodium  carbonate 
and  0.5  gram  of  niter.  Remove  tungsten  by  one  evaporation 
to  dryness.  Dissolve  in  5  c.c.  i  :  i  hydrochloric  acid;  filter; 
wash;  evaporate  to  fumes  with  10  c.c.  i  :  3  sulphuric  acid. 
Dissolve  in  10  c.c.  of  water;  wash  into  a  10  by  i  inch  tube; 
dilute  to  20  c.c.  with  water.  Add  10  c.c.  concentrated  nitric 
and  finish  as  in  steels.  Accurate  to  2  per  cent  if  0.050  gram 
are  taken  for  analysis  when  the  manganese  exceeds  i  per  cent. 

For  higher  per  cents  of  manganese  fuse  i  gram  and  remove 
tungsten  by  one  evaporation.  Convert  the  filtrate  into  sul- 
phate; rinse  it  into  a  liter  flask  and  proceed  as  given  for  high 
manganese  in  ferro-titanium.* 

Molybdenum  in  Tungsten  Powders.  Fuse  i  gram  as  for 
tungsten.  Dissolve  the  melt  in  as  little  water  as  possible. 
Filter.  Wash  with  sodium  carbonate  water.  Add  to  the 
filtrate  and  washings  4  grams  of  tartaric  acid.  Then  make 

*  Or  finish  by  the  author's  method  given  on  page  278. 


72  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

the  filtrate  very  slightly  acid  with  hydrochloric  acid.  Warm. 
Pass  H2S  for  an  hour,  or  until  the  brown  sulphide  settles  well. 
Filter  off  the  sulphide.  Wash  it  thoroughly  with  H2S  water. 
Ignite  the  precipitate  at  a  very  low  heat  until  white  or  bluish 
white.  If  it  looks  yellow,  fuse  it  with  a  little  sodium  carbonate; 
dissolve  the  melt  in  water;  add  a  crystal  of  tartaric  acid  and 
proceed  as  before  with  H2S. 

When  the  bluish  white  molybdenum  trioxide  is  obtained, 
multiply  its  weight  by  0.6666  after  deducting  the  silica,  etc.  (See 
Molybdenum  in  Steel.)  The  methods  given  for  tungsten  powder 
apply  also  to  ferro- tungsten. 

Silica  and  Iron.  Instead  of  removing  the  silica  and  iron  in 
the  analysis  of  tungsten  powder,  as  given  on  pages  68  and  69,  by 
a  fusion  with  potassium  bisulphate,  the  crude  WO3  can  be  fused 
with  twenty  times  its  weight  of  sodium  carbonate  after  the 
silica  has  been  volatilized  by  evaporation  with  15  c.c.  of  hydro- 
fluoric acid  and  five  drops  of  cone,  sulphuric  acid,  in  the  same 
manner  as  described  for  the  determination  of  the  silica  on 
page  99.  It  is  to  be  noted  that  metallic  silicon  does  not 
exist  as  such  in  tungsten  powders  but  as  oxide.  Having 
removed  the  silica  and  determined  it  as  given  on  page  99, 
and  the  above  fusion  with  sodium  carbonate  having  been 
made,  the  melt  is  dissolved  out  in  water,  and  the  iron  oxide  is 
filtered  off;  washed  thoroughly  with  water;  ignited;  weighed; 
and  deducted  from  the  WO3  plus  Fe2C>3.  The  Fe20s  so  ob- 
tained may  contain  some  alumina  and  if  the  actual  iron  con- 
tent is  desired,  the  supposed  oxide  of  iron  must  be  dissolved 
in  a  few  c.c.  of  cone.  HC1  and  the  actual  iron  determined  as 
given  on  page  70. 

It  has  been  pointed  out  that  sodium  carbonate  may  contain 
enough  iron  to  make  an  appreciable  error  in  the  tungsten  deter- 
mination by  reason  of  deducting  from  the  crude  WOs  not  only 
the  iron  that  existed  in  the  same  but  also  that  which  con- 
taminated the  sodium  carbonate  used  in  the  fusion.  The 
remedy  is  to  subtract  the  amount  of  iron  and  alumina  in  the 
carbonate  from  the  total  iron  and  alumina  found,  before  de- 


ANALYSIS   OF  TUNGSTEN   POWDER  73 

ducting  the  latter  from  the  crude  WOa.  Credit  is  due  to  Mr. 
Geo.  M.  Berry  for  emphasizing  this  point  which  is  one  phase 
of  the  general  necessity  of  running  blanks  on  all  reagents  that 
one  uses  for  any  analysis  whatsoever. 

Carbon.  The  carbon  in  tungsten  powders  can  be  deter- 
mined by  burning  the  latter  in  the  electrically  heated  furnace 
without  any  aid  to  the  combustion  other  than  the  oxygen.  The 
heating  in  the  stream  of  oxygen  should  be  continued  for  45  min- 
utes. Ferro- tungsten  should  be  as  finely  powdered  as  possible. 
It  is  mixed  with  four  times  its  weight  of  red  lead  or  peroxide  of 
lead  to  insure  complete  combustion  and  the  burning  should  be 
continued  for  30  minutes  at  least.  Blanks  must  be  determined 
on  the  oxide  of  lead  used,  and  deducted  from  the  total  CC>2 
found.  (See  Chapter  XI,  page  213.) 

Sulphur.  Sulphur  can  be  very  accurately  determined  by 
fusing  in  an  iron  crucible  i  gram  of  the  tungsten  powder  or 
the  ferro-tungsten  with  1 5  grams  of  sodium  peroxide  mixed  with 
7  grams  of  sodium  carbonate. 

The  melt  is  dissolved  out  in  water,  in  a  casserole,  and  evap- 
orated to  dryness  after  adding  an  excess  of  HC1.  Proceed 
from  this  point  to  remove  the^  tungsten,  as  given  on  page  68, 
until  the  last  traces  of  it  have  been  precipitated  with  cincho- 
nine.  The  filtrate  from  the  cinchonine  tungstate  is  then  pre- 
cipitated with  barium  chloride  and  the  sulphur  finished  as 
given  for  steels,  page  274.  Run  complete  blanks  including 
every  operation.  If  the  cinchonine  contains  excessive  amounts 
of  sulphates,  as  is  sometimes  the  case,  these  can  be  removed 
by  washing  the  crystals  on  a  porcelain  colander  with  distilled 
water  until  the  washings  no  longer  give  a  precipitation  with 
barium  chloride  solution.  This  may  cause  some  loss  of  the 
cinchonine.  A  sulphur  determination  of  any  tungsten  com- 
pound should,  without  fail,  have  this  cinchonine  treatment  to 
remove  last  traces  of  the  me ta tungstate,  otherwise  the  latter 
tungstate  will  contaminate  the  barium  sulphate,  frequently 
causing  serious  error. 


74  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

THE  DETERMINATION  OF  OXYGEN  IN  METALLIC  TUNGSTEN 
POWDER  AND  SOME  NOTES  ON  THE  DETERMINA- 
TION OF  OXYGEN  IN  STEEL. 
BY  CHARLES  MORRIS  JOHNSON. 
Received  January  22,  1913. 

It  has  been  found  a  distinct  advantage  both  in  the  manu- 
facture and  use  of  tungsten  powders  to  know  their  oxygen 
content.  In  one  of  the  laboratories  under  the  author's  direc- 
tion, this  determination  is  a  matter  of  daily  routine.  The 
method  involves  the  same  principle  used  in  the  determination 
of  oxygen  in  steel;  i.e.,  the  ignition  of  the  substance  in  a  stream 
of  hydrogen,  which  method  is  credited  to  Ledebur. 

The  electrically  heated  furnace  introduced  by  the  author  *  in 
1908  for  the  direct  determination  of  carbon  in  iron,  steel  and 
alloys  is  utilized  in  the  process  which  is  described  in  detail  in 
this  paper. 

Walker  and  Patrick,!  in  a  paper  read  at  the  Eighth  Inter- 
national Congress  of  Applied  Chemistry,  attack  the  accuracy 
of  the  Ledebur  method  on  the  ground  that  any  oxides  of  man- 
ganese or  silicon  present  in  the  steel  would  not  be  reduced.  The 
author  regards  the  Ledebur  method  as  more  practical  than  the 
proposed. new  onef  above  noted;  even  if  the  former  process 
does  not  reveal  the  total  oxygen  present  it  certainly  shows 
enough  of  it  to  furnish  a  basis  for  judgment  of  the  quality  of 
the  steel.  If  the  steel  is  sufficiently  dirty  and  poorly  melted 
in  actual  open-hearth  Bessemer  or  crucible  practice  to  contain 
oxides  of  manganese  and  silicon,  then  it  would  surely  contain 
enough  oxide  of  iron  to  condemn  it. 

The  arrangement  of  apparatus  is  indicated  in  the  drawing  and 
the  accompanying  notes.  The  towers  (or  jars),  page  77,  are  the 
author's  design  as  are  also  /,  I  and  C,  and  were  first  used  as 
part  of  a  combustion  train.f  In  this  laboratory  four  furnaces 
are  placed  side  by  side.  By  the  use  of  a  Y  tube  at  the  outlet  of 

*  /.  Am.  Chem.  Soc.,  30,  773. 

t  Proc.  8th  Intern.  Cong.  Appl.  Chem.,  21,  139;  also  this  Journal,  4,  799. 

j  /.  Am.  Chem.  Soc.,  28,  862. 


ANALYSIS  OF  TUNGSTEN  POWDER 


75 


76  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

jar  F,  one  train  from  F  to  K  can  be  made  to  serve  two  furnaces.* 
Of  course  a  separate  set  of  A,  B  and  C  is  necessary  for  each 
furnace.  If,  after  making  a  large  number  of  determinations, 
the  blank  begins  to  show  a  gradual  increase,  the  contents  of 
the  various  jars  must  be  renewed. 

METHOD. 

Blank.  Before  introducing  anything  into  the  electric  fur- 
nace, close  all  points  marked  " screw  pinch  cock."  At  B,  Fig.  i, 
make  a  connection  with  a  straight  glass  tube  instead  of  the  U 
tube  shown.  Insert  quickly  into  the  quartz  tube  (at  the  point 
marked  E)  the  porcelain  boat  that  has  been  kept  at  105°  C.  in 
an  air  bath.  Push  the  boat  into  the  center  of  the  furnace  with 
a  heavy  copper  wire  which  is  marked  to  show  how  to  place  the 
boat  in  the  hottest  part  of  the  furnace.  Stopper  the  tube 
as  quickly  and  tightly  as  possible.  Open  all  4  pinch  cocks 
and  turn  on  the  hydrogen  slowly  until  it  passes  through  the 
apparatus  at  the  rate  of  about  seventy  bubbles  per  minute. 
Allow  the  hydrogen  to  pass  through  the  cold  furnace  for  30 
minutes.  Close  all  the  pinch  cocks  and  replace  the  glass  tube 
at  B  by  the  U  tube.  Open  all  cocks  and  let  hydrogen  run  for 
another  half  hour  to  fill  the  weighing  apparatus  with  this  gas. 
Close  all  pinch  cocks  and  the  glass  cocks  on  the  U  tube.  Re- 
move the  U  tube  and  weigh  it  quickly.  Insert  the  U  tube  again, 
open  all  cocks  and  start  the  hydrogen  flow;  turn  on  the  electric 
current  in  the  furnace  and  bring  up  the  temperature  to  950  to 
1000°  C.  After  reaching  this  temperature  keep  the  heat  on 
for  two  hours  with  the  hydrogen  passing  continually.  Close  all 
pinch  cocks,  shut  off  the  hydrogen,  and  close  the  glass  cocks  on 
the  weighing  apparatus  B.  Detach  and  weigh  B.  The  differ- 
ence between  this  weight  and  the  first  weight  represents  the 
blank  to  be  deducted  from  all  determinations. 

Sample.  Dry  the  finely  ground  powder  of  the  tungsten 
metal  to  constant  weight  at  105°  C.  Put  2  or  3  grams  of  the 
powder  into  a  porcelain  boat  that  has  been  dried  at  105°  C. 

*  See  photo  No.  i. 


ANALYSIS  OF  TUNGSTEN  POWDER 


77 


78  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Place  this  in  the  cold  furnace  and  stopper  tightly  at  E.  Using 
the  glass  tube  connection  at  B,  open  the  pinch  cocks  and  allow  hy- 
drogen to  pass  through  the  cold  furnace  for  one-half  hour  to  re- 
move whatever  air  entered  when  the  charge  was  inserted.  Close 
all  pinch  cocks  and  replace  the  glass  tube  by  the  weighed  U  tube 
at  B.  Open  all  cocks,  adjust  the  hydrogen  flow  to  70  bubbles 
per  minute  and  turn  on  the  electric  current,  heating  the  furnace  to 
from  950  to  1000°  C.  Maintain  this  temperature  for  two  hours 
with  the  hydrogen  passing.  Close  all  cocks  and  turn  off  the  hy- 
drogen. Remove  and  weigh  the  U  tube.  The  increase  in 
weight  minus  the  blank  gives  the  amount  of  water  formed  by 
the  reduction  of  the  metallic  oxides  to  metal.  This  result  multi- 
plied by  1 6  and  divided  by  18.01 6  is  equivalent  to  the  weight 
of  oxygen  which  is  converted  into  percentage  by  the  usual  cal- 
culations. 

STANDARDIZATION  OF  APPARATUS. 

With  C.P.  Tungstic  Oxide.  This  material  is  prepared  as  fol- 
lows: Treat  5  grams  of  96  to  98  per  cent  tungsten  powder  in  a 
platinum  dish  with  10  c.c.  c.p.  hydrofluoric  acid.  Pour  on  this 
mixture  very  slowly  30  c.c.  of  concentrated  nitric  acid.  This 
produces  considerable  heat,  and  the  material  is  dissolved  as 
clear  as  water.  Now  add  15  c.c.  of  concentrated  sulphuric  acid, 
evaporate  to  thick  fumes,  cool,  add  from  10  to  20  c.c.  c.p.  hydro- 
chloric acid,  boil  from  3  to  4  minutes,  add  50  c.c.  of  water, 
heat,  filter,  and  wash  free  from  iron  and  sulphates  by  decanta- 
tion  in  a  600  c.c.  beaker.  Transfer  to  a  platinum  dish,  ignite 
at  a  bright  red  heat  in  a  muffle,  and  put  in  a  glass-stoppered 
bottle.  Before  using  any  of  this  material  for  a  test,  ignite  a 
portion  of  it  at  a  blast  lamp  temperature.  Immediately  after 
the  blasting  put  i  gram  of  the  oxide  in  a  porcelain  boat  dried 
at  105°  C.,  and  charge  it  at  once  into  the  furnace.  It  will 
require  at  least  6  hours  treatment  at  950  to  1000°  C.  to  reduce 
this  amount  of  oxide  and  carry  all  of  the  water  formed  over 
into  the  weighing  apparatus. 

With  Ferric  Oxide.  Dissolve  10  grams  of  low  carbon  steel  of 
very  low  phosphorus,  sulphur  and  silicon  content  in  100  c.c. 


ANALYSIS   OF  TUNGSTEN  POWDER  79 

hydrochloric  acid  in  a  liter  beaker.  Transfer  this  to  a  No.  7 
porcelain  dish  and  evaporate  to  10  c.c.  Add  100  c.c.  nitric 
acid  and  evaporate  to  20  c.c.  Add  50  c.c.  of  concentrated  nitric 
acid,  and  evaporate  to  dry  ness.  Place  the  dish  in  a  muffle  and 
heat  to  redness.  Cool,  dissolve  in  50  c.c.  hydrochloric  acid, 
add  50  c.c.  of  water,  evaporate  to  small  volume,  filter  out  insol- 
uble matter,  such  as  silicic  acid,  and  precipitate  with  filtered 
ammonia.  Wash  the  precipitate  by  decantation  until  free  from 
chlorides,  dry  in  a  porcelain  dish,  heat  to  redness  and  place 
in  a  stoppered  bottle.  Blast  a  portion  of  this  for  three  or  four 
minutes,  transfer  i  gram  quickly  to  a  porcelain  boat,  and  place 
at  once  in  the  reduction  furnace.  Pass  hydrogen  for  six  hours 
after  the  furnace  reaches  950  to  1000°  C. 

TABLE  i.      RESULTS  OBTAINED  BY  APPARATUS  DESCRIBED. 
Pure  WOs,  gave  20.69  per  cent  oxygen. 
i  gram  gave  20.70  per  cent  oxygen, 
o.  250  gram  gave  20.80  per  cent  oxygen. 
0.500  gram  gave  20.30  per  cent  oxygen. 
Average,  20.60  per  cent  plus. 

Pure  Fe2Os,  gave  30.05  per  cent  oxygen. 
0.500  gram  gave  30.16  per  cent  oxygen. 
Blanks,  0.0030  and  0.0036. 

THE  EFFECT  OF  FREE  CARBON  ON  THE  METHOD. 
It  is  an  advantage  to  have  some  excess  of  free  carbon  in 
finished  tungsten  powder,  and,  at  times,  in  the  process  of  man- 
ufacture, it  is  necessary  to  know  the  amount  of  oxygen  pres- 
ent in  a  powder  that  contains  as  much  as  3  or  4  per  cent  of 
charcoal.  Some  tests  were  made  to  see  if  the  reaction  WOs  + 
3  C  =  W  +  3  CO  might  not  occur  at  the  same  time  with  the 
desired  reaction  W03  +  6  H  =  W  +  3  H2O.  Table  2  shows 
that  the  presence  of  excessive  amounts  of  free  carbon  caused 
no  material  error  in  the  case  of  the  pure  tungsten  oxide,  but  did 
cause  low  results  when  the  carbon  content  exceeded  5  per  cent 
in  the  iron  oxide.  A  curious  feature  is  that  30  per  cent  of 
free  carbon  caused  practically  no  lower  result  than  the  addition 
of  10  per  cent. 


8o 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


TABLE   2.       RESULTS    OBTAINED    WITH    MIXTURES    OF    OXIDES 
AND  CHARCOAL. 


Grams  of  Mixture. 

Percentage  Oxygen, 

Percentage  Oxygen 

Percentage  Carbon 

W03 

Charcoal. 

Theoretical. 

Found. 

Present. 

0-544 

O.  2OI 

20.69 

20.57 

26.6 

0.300 

0.090 

20.69 

19.80 

23.0 

0.400 

0.080 

20.69 

20.32 

I6.7 

0.500 

0.060 

20.69 

20.53 

10.7 

Fe203 

0.5785 

o.ooo 

30.05 

29.84 

None 

0-473 

0.208 

30.05 

27-35 

30.5 

0.400 

0.  122 

30.05 

28.68 

23-3 

0.300 

0.089 

30.05 

27-53 

23-0 

0.500 

O.O25 

30.05 

2Q-95 

4-7 

0.500 

0.050 

30.05 

27.82 

9-7 

The  following  table  shows  the  amounts  of  oxygen  found  in 
the  various  brands  of  tungsten  powders  made  both  in  the  U.  S. 
and  abroad.  Each  numeral  represents  a  different  make. 

The  reduction  was  particularly  poor  in  the  second  lot  re- 
ceived from  the  German  manufacturer  designated  as  II  (No.  2 
in  his  second  shipment).  When  so  much  oxide  is  present  it 
can  be  easily  detected  by  the  eye,  being  equivalent  to  10.92 
per  cent  of  tungstic  oxide.  Such  so-called  metal  has  a  distinct 
brown  color. 

TABLE  3. 


Make. 

Imported  or  Domestic. 

Oxygen  Found. 

Consignment. 

I.  . 

German 

Per  cent. 
I   O2 

II  ,    . 

German 

I  .  IO 

No.  i 

II 

German 

2    26 

No  2 

III. 

German 

o  18 

IV  

German 

O    <?3 

V  

American 

O   17 

No.  i 

v 

American 

O  4.7 

No.  2 

v 

American 

I    24. 

No.  3 

VI  

American 

o  80 

VII 

American 

O   4.^ 

VII 

American 

«o  08 

VII 

American 

o  07 

ANALYSIS   OF  TUNGSTEN  POWDER 


8l 


THE  DECARBONIZATION  OF  STEEL  WHEN  IGNITED  IN  A 
STREAM  OF  HYDROGEN  FOR  THE  OXYGEN  TEST. 

In  1909  the  writer  called  attention  to  the  fact  that  hydrogen 
will  produce  a  bark,  or  decarbonized  surface,  on  steels  when  the 
latter  are  heated  in  a  current  of  this  gas.  Supplementing  this 
statement  *  the  following  tests  were  made  on  three  steels  that 
were  analyzed  for  oxygen: 


TABLE  4. 


Grams  of 
Drillings  Taken 
for  the  Oxygen 
Test. 

No.  of  Hours 
Ignited  in 
Hydrogen. 

Percentage  Carbon  Content. 

Before  Ignition. 

After  Ignition. 

Sample      I 

9.6 
16.0 
iQ-5 

i 

1.04 
i.  08 
0.83 

O.QO 
0.83 
o.  70 

Sample    II 

Sample  III  

In  the  foregoing  method  no  preheating  furnace  or  tube  is 
used  such  as  was  recommended  by  Ledebur  in  his  "Leitfaden 
fur  Eisenhutten-Laboratorien"  and  adopted  by  others  who  have 
since  written  on  this  or  similar  subjects,  thus  simplifying  mat- 
ters to  that  extent.  Also,  concentrated  sulphuric  acid  is  omitted, 
entirely,  eliminating  the  possibility  of  unpleasant,  not  to  say 
dangerous,  accidents  from  this  source. 

The  introduction  of  an  alkaline  solution  of  pyrogallol  into  the 
purifying  train  was  made  at  the  suggestion  of  Mr.  Simon  Lubow- 
sky,  in  July,  1912,  when  working  under  the  author's  direction. 
The  latter  adopted  his  suggestion  as  did  Mr.  McMillen,f  of 
The  Crescent  Steel  Works,  who  was  the  first  to  apply  the 
electrically  heated  furnace,  introduced  by  the  writer,  to  the 
determination  of  oxygen. 

*  See  "The  Formation  of  White  Scale  on  Steel  and  the  Surface  Decarboni- 
zation  of  Pipe-annealed  Steel,"  page  348. 

t  Met,  and  Chem.  Eng.,  n,  No.  2;  also  this  Journal,  Feb.,  1913. 


82  CHEMICAL  ANALYSIS   OF   SPECIAL   STEELS 

THE  PREPARATION  OF   THE  STEEL  SAMPLE  FOR  THE 

DETERMINATION  OF  OXYGEN. 

The  steel  should  be  first  thoroughly  ground  and  polished  free 
of  all  rust  and  scale  as  a  very  small  particle  of  either  oxide 
would  seriously  impair  the  accuracy  of  the  work.  The  drill 
should  be  also  free  of  rust,  grease  and  scale.  The  drilling 
should  be  proceeded  with  slowly  so  as  not  to  overheat  the  sam- 
ple as  this  will  cause  oxidation.  Any  blue  or  gold  colored 
drillings  present  indicate  overheating  during  the  drilling  or 
milling  of  the  samples  and  any  such  should  be  rejected.  10 
coarse  drillings  are  also  rejected  by  the  author;  and  only  those 
drillings  that  will  pass  a  twenty  mesh  screen  and  will  not  pass  a 
thirty  mesh  one  are  used,  unless  the  drillings  are  very  thin.  10 
to  20  grams  of  sample  are  taken  and  the  work  is  carried  out  as  in 
the  tungsten  powder.  The  drillings  are  kept  over  anhydrous 
calcium  chloride  until  used.  The  great  danger  about  the  whole 
operation  is  that  improper  sampling  may  cause  oxygen  to  be 
found  that  does  not  exist  in  the  steel.  The  drillings  are  heated 
at  950  to  1000°  C.  for  2  hours  in  the  apparatus  shown  on  page 
77,  Fig.  i. 

THE  DETERMINATION  OF  PHOSPHORUS  IN  FERRO-TUNGSTEN 

METALLIC  TUNGSTEN  POWDER,  TUNGSTEN  OXIDE 

AND  TUNGSTIC  ACID  BY  DlRECT  SOLUTION. 

BY  C.  M.  JOHNSON. 
Received  February  7,  1913. 

The  author  found  in  the  course  of  an  investigation  that  the 
practice  of  decomposing  tungsten-bearing  materials  by  fusing 
them  with  a  mixture  of  sodium  carbonate  and  potassium  nitrate, 
leaching  out  the  fusion,  acidulating  with  hydrochloric  acid,  re- 
moving the  tungstic  acid  by  several  evaporations  to  dryness, 
and  then  using  the  filtrate  and  washings  from  the  tungstic  acid 
for  the  determination  of  the  phosphorus,  gave  far  less  of  the 
latter  element  than- was  actually  present.  He  then  devised  the 
following  method  which  he  has  found  to  give  near  enough  to 
the  true  phosphorus  for  technical  purposes. 


ANALYSIS   OF   TUNGSTEN   POWDER  83 

FERRO-TUNGSTEN  . 

Add  30  c.c.  of  concentrated  nitric  acid  to  i  gram  of  the  pow- 
dered sample,  in  a  platinum  dish;  then  add  slowly  3  c.c.  of 
c.p.  hydrofluoric  acid.  Keep  the  dish  covered  with  a  watch 
glass;  warm  the  mixture.  After  warming  and  slight  boiling, 
the  material  should  dissolve  to  a  clear  solution.  Transfer  the 
solution  to  a  No.  5  porcelain  dish  and  evaporate  to  dryness;  do 
not  bake  as  there  is  danger  of  losing  phosphorus  at  this  point. 
Dissolve  this  residue  with  50  c.c.  of  concentrated  hydrochloric 
acid.  Heat  with  the  lid  on;  then  remove  the  lid  and  evaporate 
to  dryness;  do  not  bake.  Dissolve  again,  using  20  c.c.  of  con- 
centrated hydrochloric  acid;  heat;  add  50  c.c.  of  water,  stir, 
heat  and  filter  out  the  main  tungsten;  wash  with  one  part  of 
concentrated  hydrochloric  acid  diluted  with  twenty  parts  of 
water.  Evaporate  the  filtrate  and  washings  to  10  c.c.,  add 
20  c.c.  of  water,  stir  and  filter  as  before.  Evaporate  to  10  c.c., 
add  75  c.c.  of  concentrated  nitric  acid  and  heat  with  the  cover 
on  until  all  action  is  over;  remove  the  lid  and  evaporate  to  20  c.c. 
Add  50  c.c.  of  nitric  acid,  and  evaporate  to  15  c.c.  Add  20  c.c. 
of  water,  stir,  heat  and  filter  into  a  6  oz.  beaker;  wash  with 
2  c.c.  of  concentrated  nitric  acid  diluted  with  100  c.c.  of  water, 
washing  fifteen  times.  Evaporate  the  filtrate  and  washings 
in  the  beaker  to  40  c.c.  Replace  the  lid  and  add  a  slight  excess 
of  5  per  cent  solution  of  potassium  permanganate;  boil  three 
or  four  minutes.  Dissolve  the  excess  of  manganese  oxide  with 
a  little  ferrous  sulphate,  and  precipitate  the  phosphorus  with 
molybdate  solution. 

When  dissolving  ferro-tungsten  in  the  mixture  of  nitric  and 
hydrofluoric  acids,  a  porcelain  dish  can  be  used,  but  a  little 
more  hydrofluoric  acid  may  be  needed  to  secure  complete  solu- 
tion of  the  alloy  on  account  of  the  tendency  of  the  latter  acid 
to  attack  the  dish.  Further,  when  a  porcelain  dish  is  used, 
blanks  must  be  run,  using  a  standard  steel.  The  latter  is  dis- 
solved in  the  mixture  of  the  two  acids  and  the  phosphorus  de- 
termined, using  the  porcelain  dish.  If  the  standard  is  found  to 


84 


CHEMICAL  ANALYSIS   OF   SPECIAL   STEELS 


run  higher  than  it  should,  the  deduction  necessary  to  correct 
it  constitutes  the  blank  to  be  subtracted  from  the  phosphorus 
found  in  the  sample. 

Any  method  with  which  the  writer  is  acquainted,  using  a 
carbonate  and  niter  fusion  of  materials  containing  tungsten  for 
the  purpose  of  obtaining  the  percentage  of  phosphorus  therein, 
gives  only  a  fourth,  or  less,  of  the  actual  content  of  the  latter 
element.  The  following  results  are  only  a  few  of  those  ob- 
tained in  this  laboratory  and  are  given  in  proof  of  the  above 
statement. 

COMPARISON  OF  FUSION  AND  EXTRACTION  METHODS. 


Sample. 

Percentage, 
Author's 
Extraction 
Method. 

Phosphorus 
Found  by 
Fusion  with 
Na2C03+KN03 

Ferro-tungsten  No.  18                                        ... 

r   0.322 
j    0.350 

0.096 

A  high  phosphorus  pig  iron  (0.73  per  cent  P)  : 
0.5  gram  tungsten  powder  (98  per  cent  pure) 
per  gram  of  iron      .  .                              ... 

0.345 
I    0.330 

o  70 

J       0  .  088 
(       0.098 

'  '  Tungsten  cake  "  

O.IOI      ) 

\       0.095 
0.008 

Tungsten  powder  oxidized  to  WO3  at  low  red 
heat  before  extraction  .... 

O.IO2      ) 

o  113 

0.007 

TUNGSTEN  ORES. 

Here  the  procedure  differs  only  in  the  manner  by  which  de- 
composition is  effected.  Grind  the  ore  to  the  finest  possible 
state  of  division;  extract  at  nearly  boiling  temperature  with 
100  c.c.  cone,  hydrochloric  acid  in  a  No.  5  porcelain  dish. 
About  every  thirty  minutes,  add  o.i  gram  additions  of  KClOs; 
on  each  addition  of  chlorate  stir  the  sample  off  the  bottom 
of  the  dish  with  a  glass  rod.  Continue  the  heating,  addition 
of  chlorate  and  stirring  until  the  tungsten  ore  has  changed 
from  a  brown  color  to  yellow  in  case  of  the  dark  ores;  or 
from  a  light  gray  or  brown  to  a  very  bright  yellow  in  case  of 


ANALYSIS  OF  TUNGSTEN  POWDER  85 

scheelite  ore.  Evaporate  to  dryness;  cover;  add  50  c.c.  con- 
centrated HC1;  heat  10  minutes  to  dissolve  the  iron  and  man- 
ganese; add  50  c.c.  of  water  and  heat  15  minutes  to  allow  the 
tungstic  acid  to  separate  well;  cool  and  mix  in  some  paper  pulp. 
Filter  through  a  double  filter;  wash  with  one  part  of  hydro- 
chloric acid  diluted  with  twenty  parts  of  water.  Evaporate 
the  filtrate  and  washings  to  5  c.c.  and  add  75  c.c.  of  concen- 
trated HNO3;  heat  with  the  cover  on  the  dish  until  all  red 
fumes  are  gone  and  no  further  spraying  occurs;  remove  the 
cover  again  and  evaporate  to  10  c.c.;  add  50  c.c.  of  concen- 
trated nitric  and  evaporate  to  10  c.c.  again;  dilute  with  15  c.c. 
of  water  and  mix  well.  Filter  into  a  6  oz.  beaker;  wash  with 
a  i  per  cent  by  volume  solution  of  nitric  acid,  fifteen  or  twenty 
times.  Evaporate  the  filtrate  and  washings  to  40  c.c.  in  the 
beaker;  boil  with  a  slight  excess  of  permanganate  solution. 
Add  just  enough  ferrous  sulphate  to  clear  the  excess  of  the  hy- 
drated  oxide  of  manganese  and  boil  again  five  minutes.  Add 
50  c.c.  of  molybdate  solution  to  the  hot  fluid  in  the  beaker  and 
finish  the  analysis  as  given  for  ferro-tungsten. 

By  careful  heating  and  small  additions  of  the  chlorate,  to- 
gether with  further  applications  of  acid,  if  necessary,  many 
dark  ores  can  be  so  completely  decomposed  as  to  attain  a  clean 
orange  color.  The  more  complete  the  decomposition,  the  more 
perfect  will  be  the  extraction  of  the  phosphorus.  The  hard 
black  ferberites  are  the  slowest  to  yield  and  take  on  the  yellow 
color.  The  decomposition  can  be  done  to  the  best  advantage 
at  a  low  digesting  heat  and  will  require  at  least  5  or  6  hours. 

This  somewhat  lengthy  method  is  the  only  one  that  the 
author  has  found  reliable,  thus  far,  for  technical  purposes  in 
tungsten  ores.  The  latter  may  contain  all  the  way  from  slight 
traces  up  to  0.500  per  cent  phosphorus.  The  fusion  method 
with  these  ores  gives  just  as  low  results  as  with  the  ferro-tungsten. 
The  cause  of  the  low  results  is  the  formation  of  phospho-tungstic 
acid;  this  is  carried  from  the  solution  with  the  main  tungstic 
acid  that  forms  when  the  sodium  tungstate  is  decomposed  by 
acidulation  and  evaporation  with  acid. 


86  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

METALLIC  TUNGSTEN  POWDER,  TUNGSTIC  OXIDE  AND 
TUNGSTIC  ACID. 

Ignite  the  tungsten  powder  at  a  red  heat  with  frequent  stirr- 
ing until  it  is  all  converted  to  the  yellow  oxide.  Then  extract 
exactly  as  in  tungsten  ore  for  at  least  six  hours  and  finish  ac- 
cording to  the  ore  method. 

The  original  oxidation  is  best  accomplished  by  weighing  the 
sample  into  the  dish  in  which  the  extraction  is  to  be  made  and 
then  placing  dish  and  all  in  a  muffle  which  is  at  a  low  red  heat. 

Tungstic  acid  and  oxide  do  not  require  heating  to  redness. 
Their  analysis  for  phosphorus  is  exactly  like  that  for  ores  begin- 
ning with  the  hydrochloric  acid  chlorate  treatment. 

Reserve  the  tungsten  residues  that  are  filtered  out  after  the 
extractions  and  evaporations  for  the  tungsten  determination. 
The  purification  of  these  residues  will  be  made  the  subject  of 
a  later  publication. 

NOTE. —  It  may  be  well  in  this  article  to  caution  those  who 
have  occasion  to  determine  the  phosphorus  in  molybdenum 
compounds,  that  any  molybdic  acid  separating  out  of  acid  solu- 
tions containing  phosphorus  will  carry  a  considerable  amount 
of  the  latter  element  out,  forming  the  analogous  compound 
phospho-molybdic  acid. 

METHOD. 
The  Determination  of  Tin  in  Metallic  Tungsten  Powder. 

Weigh  i  gram  of  finely  ground  sample  into  a  porcelain  boat 
of  size  2 1  inches  X  \  inch.  Spread  this  material  out  in  as 
thin  a  layer  as  possible.  Place  this  boat  in  the  quartz  tube  of 
the  same  apparatus  as  is  used  for  the  determination  of  oxygen. 
Let  the  hydrogen  pass  at  950°  C.  or  thereabouts  for  one  hour. 
The  hydrogen  should  pass  through  the  furnace  considerably 
faster  than  it  does  for  oxygen  determination.  Turn  off  the 
current  and  continue  to  pass  hydrogen  until  the  furnace  is 
cooled  sufficiently,  i.e.,  below  a  red  heat,  so  that  the  hydrogen 
will  not  explode  when  the  stopper  is  removed  for  withdrawal 


ANALYSIS  OF   TUNGSTEN  POWDER  87 

of  the  boat.  All  the  contents  of  the  boat  should  now  have  the 
gray  color  of  metallic  tungsten.  Unless  it  has  this  color, 
it  should  be  returned  to  the  furnace  and  heated  further  as  before. 
When  the  material  is  properly  reduced,  remove  it  to  a  small 
agate  mortar;  pulverize  it,  taking  care  not  to  lose  any  of  the 
substance.  Then  transfer  the  finely  ground  tungsten  powder 
to  a  5  inch  casserole;  add  100  c.c.  of  concentrated  hydro- 
chloric acid;  heat  the  dish  for  6  hours  in  boiling  water,  with 
frequent  small  additions  of  potassium  chlorate.  Add  about 
i  gram  of  this  salt  every  hour.  Stir  the  material  well  off  the 
bottom  of  the  dish  with  each  addition  of  the  potassium  chlorate. 
Add  100  c.c.  of  water;  stir  well;  filter;  wash  with  dilute  hydro- 
chloric acid  water;  add  10  c.c.  of  cinchonine  solution;  dilute 
to  400  c.c.  with  water;  stir  thoroughly;  let  stand  over  night; 
filter  from  any  precipitate  of  tungsten  cinchonate;  wash  with 
solution  containing  5  c.c.  of  cinchonine  solution,  diluted  with 
500  c.c.  of  water;  add  ammonia  to  the  solution  of  the  sample 
until  the  iron  precipitate,  or  other  precipitates  that  may  have 
formed,  seems  to  dissolve  rather  slowly.  Heat  the  perfectly 
clear  solution  to  about  80°  C.;  pass  H^S  slowly  through  it  until 
the  precipitate  of  tin  sulphide  separates  out  well  This  will  take 
several  hours  passage  of  the  gas.  Filter.  Wash  with  H^S 
water.  It  will  require  about  50  to  60  washings  to  remove  the 
iron.  Burn  the  filter  paper  and  sulphides  of  tin,  copper,  molyb- 
denum, etc.,  at  a  red  heat  in  an  open  porcelain  crucible  until 
the  residue  is  of  a  grayish  white;  if  copper  is  present  there  will 
be  black  spots  in  the  ash.  If  tinged  with  red,  iron  is  present. 
In  either  case  warm  the  ash  in  the  crucible  with  10  c.c.  of  1.20 
nitric  acid,  covering  the  crucible  with  a  small  watch  glass  during 
the  heating  period  which  should  continue  until  any  slight  effer- 
vescence that  may  occur  has  ceased.  If  bismuth  be  present,  it 
is  quite  noticeably  reduced  during  the  removal  of  the  carbon 
of  the  filter  paper.  After  heating  for,  at  least,  ten  minutes,  and 
longer  if  necessary,  the  watch  glass  is  removed,  rinsing  off  its  un- 
der surface  and  allowing  the  washings  to  run  into  the  crucible. 
Evaporate  the  contents  of  the  crucible  to  dryness  and  gently 


88  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

ignite  it  until  all  nitrates  are  decomposed.  Then  weigh  the 
residue,  after  igniting  it  at  a  red  heat  for  30  minutes  to  render 
the  tin  insoluble.  This  weight  will  be  that  of  the  oxides  of  Sn, 
Cu,  Mo,  Sb,  Bi  and  a  little  Fe.  To  remove  the  Cu,  Fe  and  Bi 
warm  the  ash  in  the  crucible  with  10  c.c.  of  i  :  i  HC1,  heating 
for  10  minutes  just  below  boiling;  rinse  the  contents  of  the  cru- 
cible onto  a  small  filter;  wash  the  same  with  i  :  20  HC1  and, 
finally,  with  some  water.  Ignite  the  paper  in  the  same  crucible 
again  until  white  to  grayish  white  at  a  low  red  heat.  Moisten 
with  cone,  nitric  acid  and  ignite  again  to  oxidize  any  metal 
formed. 

If  molybdenum  is  present  extract  this  residue  with  5  or  10  c.c. 
of  strong  ammonia.  Use  ammonia  that  is  freed  from  any  sedi- 
ment or  floating  particles,  or  scales  of  glass.  Filter;  wash 
paper  with  ammonia  and  put  it  back  again  into  the  same  cru- 
cible, and  burn  the  residue  at  a  low  heat.  This  residue  will 
now  consist  of  tin  oxide  plus  a  little  silica.  Weigh  the  residue; 
and  remove  it  to  a  platinum  crucible.  Add  four  to  five  drops 
strong  sulphuric  acid,  and  then  10  c.c.  c.p  hydrofluoric  acid; 
evaporate  as  in  the  determination  of  tungsten.  Drive  off  sul- 
phuric acid;  weigh  the  white  to  grayish  white  residue  as  oxide 
of  tin.  This  weight  multiplied  by  0.7880  gives  the  equivalent 
weight  of  metallic  tin,  which  is  converted  to  percentage  by  the 
usual  calculations. 

In  the  presence  of  much  tin  and  bismuth  it  is  more  accurate  to 
proceed  as  given  in  the  foregoing  method  until  the  sulphides  of 
tin,  etc.,  have  been  filtered  and  washed  when,  instead  of  ignit- 
ing the  same,  the  mixture  of  sulphides  is  placed,  filter  and  all, 
in  a  porcelain  casserole,  covered  with  yellow  ammonium  sulphide 
and  warmed  on  a  water  bath  with  frequent  stirring  for  three 
hours.  The  pulp  and  solution  are  then  filtered  and  washed 
with  water  containing  10  c.c.  of  the  yellow  ammonium  sul- 
phide diluted  with  500  c.c.  of  water.  After  thorough  washing  the 
filtrate  and  washings  are  made  slightly  acid  with  HC1  and  sat- 
urated with  H2S  when  all  of  the  tin  will  separate  out;  it  is  then 
filtered  out;  washed  with  H2S  water;  ignited;  treated  with 


ANALYSIS   OF   TUNGSTEN   POWDER  89 

nitric  acid;  ignited  again  and  weighed  as  tin  oxide,  now  free 
of  bismuth,  all  of  the  latter  having  been  filtered  out  with 
the  paper  pulp,  as  sulphide,  after  the  ammonium  sulphide 
extraction. 

If  the  amount  of  tin  and  bismuth  in  solution  is  large,  for  ex- 
ample 100  mgs.  of  tin  and  50  mgs.  of  bismuth,  it  is  advisable 
to  again  heat  the  precipitated  sulphide  of  tin  as  before  with  the 
yellow  ammonium  sulphide,  when  the  tin  sulphide  should  be 
free  of  bismuth. 

The  combined  filtrates  from  the  two  extractions  of  the  tin 
sulphide  are  made  slightly  acid  and  the  bismuth  therein  is  pre- 
cipitated with  H2S;  washed  with  H2S  water;  ignited  at  a  low 
red  heat  in  a  porcelain  crucible;  the  oxide  of  bismuth  is  heated 
with  a  mixture  of  a  little  cone.  HNOs  and  cone.  HC1  until  all 
black  metallic  residue  is  dissolved;  it  is  then  evaporated  to 
dryness  with  an  excess  of  nitric  acid;  ignited  to  the  yellowish 
I^Os;  and  weighed  as  such  and  calculated  to  percentage  by 
use  of  the  factor  0.89655. 

For  the  separation  of  as  much  tin  and  bismuth  as  mentioned, 
use  140  c.c.  of  cone,  ammonia  saturated  with  H2S  for  each  extrac- 
tion; and  dissolve  i  gram  of  flowers  of  sulphur  in  this  amount 
of  ammonium  sulphide  before  pouring  the  latter  over  the  mix- 
ture of  the  sulphides. 


CHAPTER   IV. 

PART  II. 

SAMPLING  OF  TUNGSTEN  ORES. 
(i)  THE  JAR  MILL. 

About  two  years  ago  the  writer  installed  in  a  laboratory 
under  his  supervision  a  jar  mill  consisting  of  jars  of  five 
pounds  capacity.  The  jars  are  of  the  finest  grade  of  German 
porcelain  filled  about  f  full  of  the  highest  grade  of  hand 
picked,  imported  flint  pebbles.  These  latter  are  of  an  ap- 
proximately elliptical  shape  with  their  shorter  axis  varying 
in  length  from  five-eighths  to  one  inch.  Each  jar  is  charged 
with  9.8  pounds  of  pebbles.  The  jars  are  8.75  X  9.65  inches 
outside  measure.  The  mill  is  operated  by  an  electric  motor 
and  the  jars  are  run  at  60  r.p.m.  The  jars  are  filled  to  the 
utmost  capacity  at  which  the  pebbles  will  do  any  grinding 
at  all,  that  is,  five  pounds,  at  least,  must  be  charged  into 
each  jar.  If  an  appreciably  smaller  amount  is  used  then  the 
pebbles  do  begin  to  abrade  on  each  other  and  the  silica  con- 
tent increases.  If  much  more  than  five  pounds  are  put  in  a 
mill  of  this  size  then  the  reduction  of  the  sample  is  extremely 
slow.  The  sampling  procedure  is  as  follows:  When  the  ore  is 
received  in  lump  it  is  crushed  under  cast  iron  wheels  to  pass  an 
eight  mesh  screen.  About  eighty-five  per  cent  of  the  crushed 
material  is  much  finer  after  this  reduction,  and  would  pass  a 
thirty  mesh.  After  the  material  is  screened,  it  is  put  back  in 
the  sacks  and  a  sufficient  portion  is  taken  from  each  bag  to 
provide  a  forty  to  fifty  pound  sample.  This  is  thoroughly 
mixed  and  quartered  down  to  about  six  pounds.  Before  quar- 
tering the  fifty  pound  sample  it  is  spread  out  in  a  layer  of  not 
above  |  inch  thickness,  and  is  divided  into  squares  of  two  inches 
in  area.  From  each  square  some  ore  is  taken  for  hand  grinding, 

90 


SAMPLING   OF   TUNGSTEN   ORES 


leaving  at  least  a  remainder  of  five  pounds  for  the  pebble  mill. 
The  five  pound  sample  is  ground  in  the  jar  for  from  ten  to 
twelve  hours.  This  reduces  the  ore  to  the  fineness  of  wheat 
flour,  and  secures  an  absolutely  uniform  sample.  The  smaller 
sample  accumulated  from  the  squares  is  well  mixed  and  is  in 
turn  spread  into  a  layer  of  -g-  inch  thickness  and  sampled  again 
in  squares  to  about  ten  grams.  The  latter  amount  is  then 
ground  in  an  agate  mortar.  » 

RESULTS  OBTAINED  FROM  THE  Two  METHODS  OF  SAMPLING. 


Five  Pound  Sample 
Ground  in  the  Jar  Mill. 

Ten  Gram  Sample 
Ground  in  the  Agate 
Mortar. 

Per  cent 
WO, 

Per  cent 
SiO2 

Per  cent 
WO3 

Per  cent 
Si02 

Portuguese  wolframite  

70-59 
69.29 

66.00 

68.  81 
70.70 
70.37 
70.34 
73-58 
69.08 
71.82 
70.48 

1-87 
5-23 
2.38 

3-73 
2.04 
2.04 
2.09 
2.60 

i-95 
4.20 
1.87 

70.51 
69.30 

65-96 

68.88 
70.79 
70.46 
70.52 
73-48 
69.00 
71.88 
70.4 

1.84 
5-33 
2-34 

3-62 
2.15 
2.04 
1.85 
2.64 
1.92 
4.20 

Australian  wolframite  
Wolframite  from  the  "  Straits  "  
Wolframite    from    the    "Straits," 
Lot  A 

Portuguese  wolframite 

"  Straits  "  wolframite 

Portuguese  wolframite,  car  560,151. 
Wolframite  from  Randsburg,  Cal.  .  . 
Straits  wolframite,  car  10,155  

Canadian  scheelite 

Portuguese  wolframite,  car  52,974. 

Six  Pound  Sample 
Ground  in  the  Jar  Mill. 

Ten  Gram  Sample 
Ground  in  the  Agate 
Mortar. 

Per  cent 
WO3 

Per  cent 
SiO2 

Per  cent 
WO8 

Per  cent 
Si02 

S.  S.  Patricia,  car  58,714  

66.00 
69.23 
69.6 
69.6 

5-73 
7-47 
2-33 
i.  06 

66.00 
69.  10 

69.5 
69.7 

5-72 
7-49 
.2.40 
1.05 

California  scheelite,  car  26,440  
Australian  wolframite,  car  534,453  . 
Wolframite  S.  S.  Cleveland  W-i  .  .  . 

After  making  these  tests  extending  over  several  months  the 
author  came  to  the  following  conclusions: 

(i)  The  best  grade  of  porcelain  and  of  hand  picked  flint 
pebbles  must  be  used. 


92  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

(2)  The  jar  must  be  filled  with  enough  of  the  sample  to  pre- 
vent the  pebbles  from  rubbing  on  each  other  or  on  the  walls  of 
the  jar,  i.e.,  a  jar  calling  for  a  maximum  charge  of  five  pounds, 
for  example,  must  be  used  with  that  amount  in  it,  otherwise 
notable  amounts  of  silica  will  be  gathered  up  during  the  grind- 
ing.    On  the  other  hand  practically  no  silica  is  obtained  and 
no  appreciable  lowering  of  the  tungsten  content  was  noted 
except  in  one  instance  car   11,611  was  apparently  lowered  in 
tungsten  content  from  72.18  to  71.95. 

(3)  The  proper  amount  of  material  to  place  in  a  jar  of  a  given 
size  in  order  to  secure  perfect  grinding,  without  adding  silica, 
should  be  determined  by  experiment. 

(4)  The  great  advantages  of  this  apparatus  are  that  a  large 
sample  can  be  taken;    that  perfect  grinding  and  perfect  uni- 
formity of  sample  are  obtained;   and  that  the  grinding  goes  on 
leaving  the  operator  free  to  attend  to  other  work. 

(5)  The  only  disadvantage  is  the  first  cost,  but  in  a  large 
works  where  many  shipments  must  be  sampled,  the  saving  of 
labor  makes  the  cost  insignificant. 

(6)  The  pebble  jar  mill  sample  is  by  far  the  best  for  factory 
control  work. 

Determination  of  Tungsten  in  Tungsten  Ores. 

(2)    THE  DETERMINATION  OF  TUNGSTEN  IN  ORES  WITHOUT  A 
PRELIMINARY  FUSION. 

The  writer  has  always  refused  to  assay  tungsten  ores  or 
other  tungsten-bearing  materials  by  precipitation  as  mercur- 
ous  tungstate  for  the  reason  that  any  phosphorus,  molybdenum, 
aluminum  or  vanadium  present  would  be  precipitated  with  the 
tungsten  and  counted  as  such.  Tin  also  is  a  common  con- 
stituent of  tungsten  ores.  The  writer  has  often  encountered 
the  presence  of  this  element  in  shipments  of  wolframite  ores 
from  traces  up  to  3.50  per  cent.  The  sodium  carbonate  fusion 
of  the  ore  which  is  the  usual  preliminary  to  the  mercurous 
nitrate  precipitation  contaminates  the  sodium  tungstate  with 


ANALYSIS  OF  TUNGSTEN  ORES  93 

tin  stannate.  In  scheelite  ores  it  is  a  common  thing  for  the 
phosphorus  to  be  as  high  as  0.150  per  cent  and  sometimes 
as  much  as  0.350  per  cent.  Slimes  and  other  low  grade  con- 
centrates are  especially  liable  to  be  high  in  this  element.  The 
writer  has  had  some  residues  very  rich  in  tungsten  running  to 
0.400  per  cent.  Alumina  is  a  frequent  constituent  to  be  guarded 
against.  Again,  as  is  well  known,  it  is  extremely  difficult  to 
wash  sodium  salts  out  of  tungstates  precipitated  from  a  so- 
lution of  the  former  by  mercurous  nitrate. 

After  some  years  experience  in  this  line  of  analytical  work, 
a  method  was  evolved  which  is  perfectly  fair  both  to  buyer  and 
seller.  It  avoids  the  tedium  of  the  sodium  carbonate  fusion  of 
the  main  sample  and  all  of  the  unpleasantness  and  inherent 
inaccuracies  of  the  mercurous  precipitation.  After  more  than 
two  years  almost  daily  use  of  this  method  the  author  now  gives 
it  in  detail  feeling  confident  that  those  having  experience  in 
this  line  of  analytical  work  will  come  to  see  its  advantages  and 
will  adopt  it  as  giving  the  true  tungsten. 

METHOD. 

The  ore  is  ground  to  the  finest  flour  either  by  hand  in  the 
agate  mortar,  or  in  the  laboratory  jar  mill;  after  drying  this 
powder  for  two  hours  at  105°  C.,  one  gram  of  it  is  weighed 
into  a  4!  inch  casserole  of  R.  B.  type  with  porcelain  handle, 
loo  c.c.  of  cone,  hydrochloric  are  poured  on  the  ore;  the  dish 
is  covered  with  a  watch  glass  and  heat  is  applied  for  one  hour, 
keeping  the  acid  below  boiling.  200  mgs.  of  crystals  of  potas- 
sium chlorate  are  now  quickly  added,  covering  the  casserole 
again.  After  the  first  violent  action  is  over,  the  ore  is  carefully 
and  completely  stirred  off  the  bottom  of  the  casserole  and  the 
mild  digesting  heat  is  continued  for  another  hour  when  the 
same  amount  of  chlorate  is  again  added  and  the  sample  is  again 
stirred  up  and  so  on  until  about  2  grams  of  the  chlorate  have 
been  consumed  and  the  ore  has  been  thoroughly  decomposed  as 
shown  by  its  color  having  changed  to  bright  yellow,  or  in  some 
ores  to  an  orange  shade.  Scheelite  requires  4  hours  of  this 


94  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

treatment  for  decomposition;  the  dark  ores,  wolframite  and  fer- 
berite,  turn  yellow  in  6  hours.  The  watch  glass  is  then  removed 
and  its  under  side  is  rinsed  off  with  water,  allowing  the  rinsings  to 
run  into  the  casserole,  the  contents  of  which  are  now  evaporated 
to  dryness  on  a  graphite  bath,  consisting  of  a  six  inch  pudding 
pan  filled  a  little  over  half  full  with  chip  graphite.  Each  unit  is 
heated  by  an  ordinary  Bunsen  burner  and  requires  but  very  little 
gas,  a  flame  from  i  to  i  J  inches  in  length  being  sufficient  for  all 
kinds  of  evaporations.  The  layer  of  graphite  is  from  f  to  i  inch 
thick.  This  enameled  pan  is  mounted  on  a  clay  flame  guard  or 
support.  If  it  is  desired  to  raise  the  temperature  of  the  dish  to  a 
dull  red,  the  pan  can  be  removed  and  the  flame  length  increased. 
This  combination  is  acidproof  to  a  practical  extent;  occasion- 
ally it  becomes  necessary  to  remove  the  Bunsen  burner  and  pour 
a  little  i  :  i  hydrochloric  acid  through  the  tube  to  clear  it 
out.  After  rinsing  out  the  acid  with  water,  it  is  ready  for  use 
again.  The  graphite  is  indestructible  and  the  whole  outfit  is 
quite  inexpensive  and  lasts  a  long  time.  Illustration  No.  34 
shows  twenty-four  of  these  units  in  use  and  No.  33  gives  a  closer 
view  of  a  portion  of  a  group.  The  outside  depth  of  the  pan 
is  if  inches.  (See  page  415;) 

After  evaporating  the  decomposed  ore  to  dryness  30  c.c. 
of  cone,  hydrochloric  acid  are  poured  on  it;  heat  is  applied; 
70  c.c.  of  water  are  added,  followed  by  30  minutes  further 
warming,  and  some  stirring.  The  crude  tungstic  acid  and 
silica  are  filtered  through  a  double,  n  cm.  ashless  filter.  Before 
performing  the  filtration,  a  f  inch  ball  of  ashless  filter  pulp  is 
thoroughly  mixed  with  the  tungstic  acid  to  hasten  filtration 
and  secure  a  perfect  washing.  The  mixture  on  the  filter  should 
be  washed  with  great  care,  giving  it  not  less  than  sixty  wash- 
ings with  i  :  30  hydrochloric  acid  to  insure  removal  of  potas- 
sium salts.  If  the  glass  rod  or  the  casserole  shows  yellow  stains 
of  tungstic  acid,  these  can  be  removed  by  pouring  over  them 
a  few  drops  of  cone,  ammonia.  This  solution  is  then  rinsed 
with  a  thin  jet  of  water  into  the  filtrate  and  washings  from 
whence  it  is  recovered  along  with  any  metatungstates  as  fol- 


ANALYSIS  OF   TUNGSTEN  ORES  95 

lows:  50  c.c.  of  cinchonine  solution  are  stirred  into  the  filtrate 
and  washings  which  are  then  allowed  to  stand  for  from  6  to  12 
hours  to  permit  the  last  traces  of  the  tungsten  to  separate  out. 
It  may  be  of  interest,  in  passing,  to  state  that  when  determining 
sulphur  in  tungsten-bearing  materials  of  any  kind  by  the  barium 
sulphate  method,  the  writer  always  first  removes  the  last  traces 
of  tungsten  that  are  almost  certain  to  be  present  by  means  of 
12  hours  standing  with  cinchonine  added.  It  is  easily  seen 
that  a  few  milligrams  of  tungstic  acid  contaminating  the  barium 
sulphate  would  cause  a  serious  error.  Cinchonine  used  for  such 
work  must  be  first  washed  free  of  sulphates  before  using  it. 
This  can  be  easily  done  by  placing  the  crystals  on  a  large  filter 
paper  and  rinsing  them  with  distilled  water  until  the  washings 
no  longer  give  a  cloudiness  with  barium  chloride.  Any  tung- 
sten-cinchonine  precipitate  must  be  washed  with  water  con- 
taining some  cinchonine  solution  as  the  precipitate  is  soluble, 
or  runs  through  the  filter  if  washed  in  the  same  manner  as  the 
tungstic  acid. 

The  filter  papers  carrying  the  tungstic  acid,  and  that  obtained 
by  the  cinchonine  are  dried  in  an  air  bath  and  then  smoked  off 
in  a  20  c.c.  platinum  crucible.  The  heat  is  then  raised  to  low 
redness  only,  and  the  heating  is  continued  until  the  residue  is 
yellow  and  free  of  carbon.  This  ash  is  cooled  in  a  desiccator 
and  weighed  as  WO3  plus  some  Fe203,  A12O3,  Sn02,  Mn304, 
CaO  and  all  of  the  Si02.  For  extreme  accuracy  in  silica  the 
filtrate  and  washings  from  the  tungstic  acid  should  be  evapo- 
rated again  to  dryness  before  adding  the  cinchonine;  the  residue 
dissolved  as  before  in  hydrochloric  acid  and  water;  any  small 
residue  of  WO3  plus  SiO2  so  obtained  is  filtered  out;  washed; 
burned  with  the  principal  precipitate  and  then  the  cinchonine 
solution  is  added  to  get  the  final  traces  of  dissolved  meta- 
tungstates. 

The  weighed  residue  consisting  of  total  WO3  plus  SiO2  plus  the 
other  oxides  mentioned  is  now  evaporated  with  from  five  to  ten 
drops  of  cone,  sulphuric  acid  together  with  15  c.c.  of  c.p.  hy- 
drofluoric acid  in  a  muffle  furnace  lined  with  inch  asbes- 


g6  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

tos  board  to  prevent  bits  of  brick  from  dropping  in  the 
work.  The  writer  uses  for  these  evaporations  a  small  rever- 
beratory  furnace.  The  gas  flame  is  not  allowed  to  come  above 
the  bridge  wall.  By  heating  in  this  manner  there  is  never  any 
danger  of  loss  of  analyses  by  spattering.  (See  page  363.) 

The  crucible  is  left  in  this  drying  furnace  until  the  heavy 
white  fumes  of  sulphuric  anhydride  are  no  longer  given  off. 
The  crucible  is  raised  to  a  dull  red  heat  on  a  Chaddock  burner 
and  then  cooled  in  a  desiccator  and  weighed  again.  The  dif- 
ference between  this  weight  and] the  weight  of  the  WO3,  etc., 
should  equal  the  silica  present  in  the  ore.  But  if  the  per  cent 
so  found  should  exceed  8  per  cent  SiO2,  then  it  is  safer  to  repeat 
this  evaporation  to  insure  the  complete  removal  of  the  silica. 
The  author  has  found  that  this  second  evaporation,  with  addi- 
tional sulphuric  and  hydrofluoric  acids,  should  in  no  case  be 
omitted  when  the  silica  content  reaches  from  30  to  60  per  cent  as 
it  often  does  in  unconcentrated  ores  and  slimes.  Titanic  oxide 
is  frequently  present  with  the  W03,  etc.,  and  for  this  reason 
the  sulphuric  acid  should  always  be  added  in  at  least  the  quan- 
tity specified  to  prevent  its  volatilization  as  fluoride. 

After  weighing  the  now  silica-free  W03,  etc.,  it  is  fused  at  a 
bright  red  heat  with  twenty  times  its  weight  of  anhydrous  sodium 
carbonate.  It  is  kept  molten  for  twenty  minutes.  The  melt  is 
dissolved  in  hot  water  in  a  100  c.c.  platinum  dish,  or  if  no  plati- 
num is  available,  then  the  fusion  can  be  leached  in  a  porcelain 
vessel,  but  in  the  cold,  as  otherwise  the  porcelain  will  be  attacked 
and  the  accuracy  of  the  analysis  will  be  impaired. 

If  the  water  solution  of  the  sodium  carbonate  fusion  of  the 
silica-free  W03  has  a  greenish  tint  due  to  the  formation  of  sodium 
manganate,  a  few  drops  of  alcohol  are  added  and  the  solution  is 
warmed  until  this  color  disappears,  the  manganese  completely 
precipitating  as  hydrated  oxide.  A  little  paper  pulp  is  added; 
the  various  oxides  are  filtered  out;  washed  repeatedly  to  en- 
tirely remove  the  sodium  salts;  ignited  at  a  red  heat  to  remove 
the  carbon.  If  the  residue  in  the  crucible  sinters  on  ignition 
it  is  imperfectly  washed  and  contains  sodium  salts,  and  a  repe- 


ANALYSIS   OF   TUNGSTEN   ORES  97 

tition  of  the  fusion,  solution  and  washing  is  necessary.  It 
is  safer  to  fuse  the  ignited  oxides  again  in  any  case  if  their 
total  weight  exceeds  4  or  5  mgs.,  as  part  of  this  weight  is  almost 
certain  to  be  WO3.  After  the  second  fusion,  solution,  washing, 
and  ignition,  the  oxides  are  weighed  and  their  amount  is  de- 
ducted from  the  weight  of  WO3  obtained  after  expelling  the 
silica.  The  remainder  represents  the  total  WO3  plus  any  tin 
and  aluminum  oxides  that  may  have  gone  into  solution  as  stan- 
nate  and  aluminate  of  sodium.  To  correct  for  these  two  ele- 
ments the  nitrates  and  washings  from  the  two  fusions  of  the 
oxides  of  W03,  etc.,  are  made  distinctly  acid  with  hydrochloric 
acid,  and  then  strongly  ammoniacal  with  filtered  ammonia. 
The  volume  of  the  filtrates  and  washings  before  acidulation 
and  addition  of  ammonia  should  be  not  less  than  500  c.c. 
After  adding  the  excess  of  ammonia,  the  solution  should  be 
clear,  any  tungstic  acid  that  may  have  formed  on  acidulating 
having  completely  dissolved  in  the  excess  of  ammonia.  The 
solution  is  now  warmed  for  an  hour  when  any  aluminum  or  tin 
present  will  gradually  separate  out  as  snow  white  flakes.  These 
are  then  filtered  out  and  washed  with  ammonium  nitrate  water 
(5  grams  of  the  nitrate  dissolved  in  500  c.c.  of  water),  mixing  in 
a  little  paper  pulp,  and  washing  at  least  fifty  times  to  insure 
removal  of  soda  salts.  The  filter  is  ashed,  ignited  and  weighed, 
and  the  weight  is  deducted  from  the  weight  of  WO3  plus  tin 
and  aluminum  oxides  last  referred  to.  The  remainder  con- 
stitutes the  pure  WO3  in  the  sample  and  is  then  calculated  to 
percentage  as  usual. 

The  foregoing  method  is  not  interfered  with  in  case  niobium 
and  tantalum  are  present,  as  the  precautions  given  for  the  re- 
moval of  the  various  oxides  mentioned  will  also  eliminate  M^Os 
and  Ta2O5. 


CHAPTER   IV. 

PART  III. 

TUNGSTEN,  SULPHUR,  SILICON,  MANGANESE  AND 

PHOSPHORUS  IN  TUNGSTEN   STEEL  AND 

CHROME  TUNGSTEN  STEEL. 

First  Method  for  Tungsten  in  Steel. 

IF  the  sample  contains  considerable  chromium  and  tungsten, 
proceed  as  follows:  Weigh  from  ij  to  2  grams  of  drillings  (see 
pages  218-223)  frrto  a  No.  5  Royal  Berlin  porcelain  evapo- 
rating dish.  Add  slowly  to  the  drillings,  keeping  the  dish 
covered  with  a  watch  glass,  a  mixture  of  30  c.c.  cone,  hydro- 
chloric acid  (1.20  specific  gravity)  and  30  c.c.  cone,  nitric  acid. 
Mix  the  two  acids  thoroughly  before  applying  them  to  the 
steel  if  phosphorus  is  wanted.  Heat  until  action  ceases,  and  if 
the  residue  in  the  bottom  of  the  dish  is  not  bright  yellow,  re- 
peat the  addition  of  acid  and  continue  to  heat  the  dish  until 
the  tungsten  residue  is  a  clean  yellow.  Then  remove  the  cover 
and  evaporate  the  contents  of  the  No.  5  dish  to  15  c.c.  Keep 
the  heat  low  enough  to  prevent  spattering.  Do  the  evaporat- 
ing on  a  graphite  or  sand  bath.  A  six  inch*  pudding  pan  filled 
two-thirds  full  of  graphite  heated  by  an  ordinary  Bunsen  burner 
makes  a  simple  contrivance  for  the  evaporations.  The  pan  can 
be  set  on  a  tripod  or  an  earthenware  flame  guard  with  the  burner 
directly  under  the  center  of  the  pan.  With  such  an  arrangement, 
a  flame  an  inch  long  will  furnish  sufficient  heat.  The  guard 
answers  the  twofold  purpose  of  supporting  the  pan  and  shielding 
the  flame  from  currents  of  air.  The  earthenware  has  the  addi- 
tional advantage  of  being  acidproof.  Add  50  c.c.  cone,  nitric 
acid.  Put  the  watch  glass  on  the  dish  and  heat  until  action  ceases. 

*  See  photo  33,  page  415. 
98 


TUNGSTEN,  SULPHUR,  SILICON,  MANGANESE,  ETC.,  IN  STEELS     99 

Remove  the  cover  and  evaporate  to  15  c.c.  Again  add  50  c.c. 
cone,  nitric  acid  and  evaporate  to  hard  dryness.  Ignite  the  dish 
and  its  contents  to  a  dull  red,  raising  the  heat  slowly  to  prevent 
cracking.  Set  the  dish  over  a  bare  flame -for  this  purpose.  The 
terra  cotta  flame  guard,  with  the  pan  removed,  answers  quite 
well  for  a  support  during  the  ignition.  Lower  the  flame  slowly 
and  set  the  dish  on  a  warm  place,  cooling  it  gradually.  When 
the  dish  is  just  warm,  pour  into  it  50  c.c.  of  cone,  hydrochloric 
acid.  Put  the  cover  on  and  heat  to  slow  boiling.  Continue  to  boil 
until  the  residue  in  the  bottom  of  the  dish  is  bright  yellow.  Then 
remove  lid  and  evaporate  to  51  c.c.  Cool,  and  add  30  c.c.  dis- 
tilled water  and  ashless  paper  pulp.  Filter  on  a  double  u  cm. 
ashless  filter  (a  double  filter  will  run  faster  than  a  single  one) ; 
wash  with  i  :  20  hydrochloric  acid  until  the  washings  give  no  test 
for  iron  with  potassium  or  ammonium  sulphocyanate.  Return 
the  filtrate  and  washings  to  the  No.  5  dish  for  concentration. 

Roast  the  paper  out  of  the  residue  of  tungstic  and  silicic  acids 
in  a  weighed  20  c.c.  platinum  crucible.  Do  not  heat  tungstic 
acid  to  a  bright  red,  as  it  slowly  sublimes  at  high  temperature. 
When  the  ash  is  bright  yellow,  free  from  black,  cool  in  a  desic- 
cator and  weigh.  This  weight  will  consist  of  mainly  tungstic 
acid  and  silica  contaminated  with  a  small  quantity  of  oxides 
of  iron,  and  chromium,  also,  if  the  latter  element  be  present. 
Add  three  drops  of  i  :  3  sulphuric  acid  to  the  residue,  and  fill 
the  crucible  two-thirds  full  with  c.p.  hydrofluoric  acid.  Evap- 
orate in  a  good  draft  to  moist  dryness.  Drive  off  the  sulphuric 
acid  by  heating  the  crucible  near  the  top.  When  all  heavy 
fumes  are  gone,  heat  to  low  red  and  weigh  as  W03  +  Fe203 
+  Cr203.  The  difference  between  this  weight  and  the  first 
weight  is  the  silica  which  has  been  volatilized.  This  loss  of 
weight  multiplied  by  47.02  and  divided  by  the  weight  of  sample 
taken,  equals  the  per  cent  silicon  present  in  the  steel.  In  the 
meantime  the  filtrate  and  washings  from  the  first  filtration 
should  be  evaporating  until  a  slight  ring  of  basic  iron  forms 
around  the  margin  of  the  fluid.  This  ring  dissolves  rather 
slowly  when  the  dish  is  rocked  backwards  and  forwards.  In 


100  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

other  words,  leave  only  enough  acid  to  keep  the  iron  in  solution. 
(However,  care  must  be  taken  not  to  overdo  the  removal  of 
the  excess  of  acid,  as  basic  iron  may  separate  in  the  solution 
when  it  is  heated  for  the  precipitation  of  phosphorus.)  Add 
20  c.c.  of  water;  filter  through  a  9  cm.  ashless  filter  into  a  150 
c.c.  beaker.  Wash  the  residue  on  the  filter  until  all  yellow 
color  due  to  chloride  of  iron  is  gone.  About  15  washings  should 
suffice.  Wash  every  other  time  with  i  :  20  hydrochloric  acid.  If 
the  volume  of  the  filtrate  and  washings  is  over  50  c.c.  reduce 
it  to  that  amount  by  evaporation.  Heat  to  boiling,  remove 
from  fire,  precipitate  with  molybdate  solution,  and  finish  the 
phosphorus  as  in  steels.  The  residue  obtained  from  the  second 
evaporation  of  original  filtrate  from  the  tungstic  acid,  etc., 
after  being  washed  free  of  color  of  iron  chloride,  is  further  washed 
free  of  iron  test  and  burned  off  in  the  same  platinum  crucible 
with  the  residue  from  which  the  silica  was  removed  by  hydro- 
fluoric acid.  This  total  residue  which  constitutes  the  tungsten 
oxide  plus  small  quantities  of  iron  and  chromium  oxides  is 
weighed  again.  If  the  original  tungstic  acid  was  thoroughly 
clean  and  yellow  before  the  first  evaporation  to  15  c.c.,  then 
the  amount  of  chromium  oxide  is  negligible. 

The  WO3  +  Fe203  +  Cr2O3  residue  is  fused  with  five  grams 
of  carbonate  of  soda.  The  melt  is  dissolved  with  hot  water. 
The  small  residue  of  iron  is  filtered  out  and  washed  free  of  car- 
bonate. It  is  burned  to  a  red  flake  in  the  same  crucible,  which 
meanwhile  has  been  thoroughly  rinsed  free  of  carbonate  with 
distilled  water.  The  residue  is  weighed  and  its  weight  de- 
ducted from  the  weight  of  the  WO3  +  Fe203  +  Cr203. 

If  the  filtrate  from  the  carbonate  fusion  is  quite  yellow,  make 
it  acid  with  sulphuric  acid,  boil  with  a  slight  excess  of  perman- 
ganate, and  determine  the  chromium  as  in  steels.*  Calculate 
the  milligrams  of  chromium  found  to  chromic  oxide,  and  deduct 
it  from  the  WO3  +  Cr2O3.  The  remainder  is  the  tungsten 
oxide,  which  multiplied  by  79.31  and  divided  by  the  weight 
taken  for  analysis  gives  the  percentage  of  tungsten.  If  the 

*  Or  determine  the  chromium  by  color,  page  31. 


TUNGSTEN,  SULPHUR,  SILICON,  MANGANESE,  ETC.,  IN  STEELS    IOI 

filtrate  from  the  sodium  carbonate  fusion  is  only  slightly  yellow, 
the  chromium  may  be  ignored  in  the  calculations. 

(A)  An  excellent  way  to  remove  oxides  of  silicon,  iron*  and 
chromium  from  the  tungstic  oxide  is  to  fuse  with  five  grams  of 
potassium  bisulphate.  This  fusion  can  be  made  quickly.  Heat 
the  crucible  at  first  to  a  very  low  heat,  below  redness,  until  the 
bisulphate  is  molten  and  slight  fumes  of  sulphuric  anhydride 
appear.  Then  raise  the  heat  carefully  to  low  redness.  Keep 
the  lid  on  the  crucible,  raising  it  only  slightly  to  observe  the 
progress  of  the  fusion.  When  redness  has  been  reached  and 
all  danger  of  spattering  is  over,  raise  the  lid,  and  if  the  contents 
of  the  crucible  are  in  a  state  of  transparent  fusion,  with  no  yellow 
specks  left  undissolved,  the  fusion  is  completed.  One  can  see 
the  bottom  of  the  crucible  through  the  transparent  molten 
mass,  and,  if  only  pure  white  flakes  of  silicic  acid  are  floating 
about,  the  melt  is  perfect.  Cool.  Dissolve  in  10  grams  of 
ammonium  carbonate  and  100  c.c.  of  water,  placing  the  cru- 
cible in  the  ammonium  carbonate  solution  contained  in  a  small 
casserole.  Warm  the  casserole  slightly  to  hasten  matters. 
Keep  it  covered  with  a  watch  glass  to  prevent  loss  during  heat- 
ing. (Use  a  casserole  if  a  platinum  dish  cannot  be  had.)  Filter, 
adding  a  little  paper  pulp.  Wash  with  water  containing  am- 
monium carbonate  until  the  washings  are  no  longer  milky 
when  acidulated  with  a  few  drops  of  hydrochloric  acid  and 
tested  with  barium  chloride.  Then  wash  10  times  more.  Ig- 
nite and  weigh  in  the  same  crucible,  and  deduct  the  residue, 
which  consists  of  all  of  the  SiO2,  C^Os  and  Fe20a,  from  the 
WOs,  etc.,  and  calculate  to  percentage.  The  residue  of  SiO2,  if 
not  pure  white,  is  evaporated  with  hydrofluoric  and  sulphuric 
acid  in  the  usual  way,  and  the  loss  of  weight  constitutes  the 
silicon  present  in  the  steel  when  multiplied  by  47.02  and  di- 
vided by  the  weight  taken  for  analysis. 

f  The  sulphur  in  such  steels  should  be  obtained  by  fusing  2 

*  See  bottom  of  page  72  relative  to  iron  in  sodium  carbonate  used  to  make  the 
fusion  for  the  removal  of  the  iron. 

f  Read  page  102  on  sulphur  in  chrome-tungsten-vanadium  steels. 


102  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

grams  of  thin  drillings  with  20  grams  of  sodium  carbonate  and 
five  grams  of  potassium  nitrate.  Dissolve  in  water,  filter,  wash, 
roast,  fuse  again,  acidulate  with  HC1,  evaporate  combined  ni- 
trates to  dryness  twice,  filter  after  each  evaporation,  washing 
with  i  :  20  HC1;  precipitate  the  filtrate  with  barium  chloride 
and  finish  as  in  gravimetric  sulphur  in  steels.  Make  blank 
determination  on  like  amount  of  the  flux  and  acids,  proceeding 
exactly  as  in  actual  analysis,  and  deduct  the  sulphur  found  from 
that  found  in  the  fusion  of  the  steel.  Multiply  the  weight  of 
barium  sulphate  less  that  found  in  the  blank  by  13.73,  and 
divide  by  the  weight  of  sample  taken  for  analysis  to  obtain  the 
per  cent  of  sulphur.  The  sulphur  can  also  be  obtained  by 
direct  solution  in  nitric  acid,  in  all  steels  that  will  dissolve  in 
it.  Finish  as  in  plain  steel. 

Manganese.  Proceed  as  for  manganese  in  steel  when  chro- 
mium is  present,  digesting  the  sample  thoroughly  with  the 
mixture  of  acids  as  given,  but  omit  the  use  of  zinc  oxide  unless 
chromium  be  found.  (See  page  15.) 

THE  GRAVIMETRIC  DETERMINATION  OF  SULPHUR  nsr 

CHROMIUM-TUNGSTEN-VANADIUM  STEEL 

WITHOUT  A  FUSION. 

Dissolve  4  or  5  grams  of  drillings  in  200  c.c.  of  cone,  nitric 
acid  mixed  with  100  c.c.  of  cone,  hydrochloric  acid  using  an 
800  c.c.  beaker.  After  the  first  action  is  over  place  the  beaker 
on  a  graphite  bath  (see  page  415)  and  heat  without  boiling 
Stir  the  residue  off  the  bottom  of  the  beaker  at  intervals  of  a 
half  hour.  If,  after  an  hour  and  a  half  of  this  digestion  with 
the  mixture  of  acids,  the  residue  on  the  bottom  of  the  beaker  is 
not  a  clean  yellow  but  still  looks  dark,  especially  in  the  layer 
touching  the  glass,  then  a  fresh  mixture  of  equal  quantity  should 
be  poured  into  the  beaker  and  the  stirring  and  digestion  con- 
tinued until  the  entire  insoluble  portion  is  a  clear,  bright  yellow, 
putting  in  a  third  mixture  if  necessary.  The  decomposition 
having  been  effected,  the  contents  of  the  beaker  are  transferred 


TUNGSTEN,  SULPHUR,  SILICON,  MANGANESE,  ETC.,  IN  STEELS     103 

to  a  600  c.c.  casserole  and  evaporated  on  the  graphite.  Before 
the  transfer  to  the  casserole  is  made,  2  grams  of  sodium  car- 
bonate are  added  to  the  solution  and  stirred  in  well.  This  is 
to  form  with  the  sulphuric  acid  present  sodium  sulphate.  Evap- 
orate to  dryness.  Cool;  add  100  c.c.  of  cone.  HC1;  cover; 
heat  until  all  but  the  yellow  residue  of  tungstic  acid  is  in  solu- 
tion; evaporate  again  to  dryness;  dissolve  as  before  with  50 
c.c.  of  HC1  and  evaporate  to  20  c.c.  Add  to  the  cool  solution, 
150  c.c.  of  water;  heat  and  stir;  add  paper  pulp  and  filter; 
wash  with  i  :  40  HC1;  add  20  c.c.  of  cinchonine  solution  and 
let  stand  for  several  hours,  preferably  until  the  next  day  to 
remove  the  last  traces  of  meta tungstic  acid;  filter;  wash  with 
cinchonine  water  (5  c.c.  of  cinchonine  solution  to  500  c.c.  of 
water)  20  times.  Heat  the  filtrate  and  washings  to  boiling 
and  precipitate  the  sulphuric  acid  formed  with  25  c.c.  of  a  sat- 
urated solution  of  barium  chloride  and  finish  the  determination 
as  in  plain  steels,  page  274.  This  method  is  of  course  applica- 
ble to  plain  chromium  steels  and  nickel  steels  which  give  low 
results  with  the  ordinary  evolution  method  as  given  for  plain 
steels,  when  several  per  cents  of  either  or  both  of  these  elements 
are  present.  The  cinchonine  solution  referred  to  is  given  on 
page  109.  Run  blanks  repeating  every  operation  and  deduct 
the  sulphur  so  found. 

THE  EVOLUTION  APPARATUS  FOR  THE  DETERMINATION 
OF  SULPHUR  IN  PLAIN  CARBON  STEELS. 

The  bulb  funnel  referred  to  on  page  269  is  shown  at  H  in 
Fig.  2.  At  D  the  thick  wall,  10  X  i  inch,  containing  the  am- 
moniacal  cadmium  chloride  solution  is  given.  The  tube  F 
with  its  four  branches  distributes  the  hydrogen  to  each  dis- 
solving flask  E.  On  each  branch  a  screw  pinch  cock,  not 
shown  in  the  cut,  is  located  at  the  point  G  to  shut  off  the 
hydrogen  from  any  one  flask  E.  The  delivery  tubes  are  as 
shown  at  C. 


104 


CHEMICAL  ANALYSIS   OF   SPECIAL  STEELS 


*FlG.    2. 


THE  DETERMINATION  OF  SULPHUR  IN  ALLOY  STEELS  BY 

HEATING  THE  INSOLUBLE  RESIDUE  TO  BRIGHT  REDNESS 

IN  A  STREAM  OF  ACID  CARRYING  HYDROGEN. 

In  1909  the  writer  in  the  first  edition  of  this  book,  see  pages 
53  and  273,  called  attention  to  the  fact  that  only  a  portion  of 
the  sulphur  is  obtained  by  the  evolution  as  ordinarily  applied 
to  plain  carbon  steels.  In  some  highly  alloyed  steels,  notably 
the  chrome-tungsten  steels,  as  little  as  one-twenty-fifth  of  the 
true  sulphur  is  so  found.  The  writer  has  an  experimental  steel 
containing  0.250  per  cent  sulphur  that  shows  but  o.oio  per 
cent  sulphur  by  the  ordinary  evolution  method  as  given  for 
plain  carbon  steels.  This  steel  contains  about  3  per  cent  chro- 
mium and  17  per  cent  tungsten  and  0.49  per  cent  carbon. 

The  writer  tried  many  schemes  to  overcome  the  failure  of 
the  evolution  methods  with  no  particular  success  until  the 
autumn  of  1911  when  the  following  plan  was  worked  out  which 
gives  practically  all  of  the  sulphur  by  evolution  as  hydrogen 
sulphide. 

*  Designed  some  years  ago  by  Dr.  E.  S.  Johnson. 


TUNGSTEN,  SULPHUR,  SILICON,  MANGANESE,  ETC.,  IN  STEELS     105 


r~c£^-i  r-C^-V. 


FIG.  3. 


From  i  to  5  grams  of  steel,  depending  on  the  amount  of 
sulphur  present,  are  dissolved,  exactly  as  given  on  pages  269  to 
271  and  the  sulphur  so  obtained  is  determined.  The  insoluble 
residue  is  filtered  off  onto  the  same  kind  and  size  of  filter  as 
was  used  to  retain  the  cadmium  sulphide,  see  page  270.  Any 
of  the  insoluble  black  carbide  adhering  to  the  walls  of  the  flask 
E,  Fig.  2,  is  removed  by  shaking  around  in  it  a  small  wad  of  filter 
pulp.  The  total  insoluble  residue  is  then  placed  in  a  15  X  120 
mm.  clay  boat  and  shoved  into  the  tube  F,  shown  in  Fig.  3.  The 
present  apparatus  differs  from  the  original  one  in  that  a  quartz 
tube,  having  a  tapered  outlet  of  the  same  design  as  illustrated 
for  carbon  combustions  on  page  244,  is  now  used.  The  outlet 
end  being  tapered  has  no  rubber  stopper  so  that  the  tube  L  is 
connected  with  the  outlet  of  the  evolution  tube  with  a  short  piece 
of  rubber  tubing  instead  of  a  rubber  stopper.  The  rubber 
stopper  was  extremely  unsatisfactory  as  it  always  gave  more 
or  less  sulphur.  It  was  found  very  important  to  avoid  all  cool- 
ing at  the  outlet  as  low  results  were  obtained  when  the  outlet 
end  was  kept  cold  with  wet  wrappings,  hence  this  end  of  the 
evolution  tube  was  allowed  to  get  quite  warm  but  not  hot 
enough  to  decompose  the  sulphur  in  the  rubber  tube  connecting 
with  L,  and  all  cooling  devices  were  omitted  from  the  outlet  0 
but  rigidly  adhered  to  at  the  inlet  end  near  F.  The  Kipp  A 
contains  the  stick  zinc  and  i  :  i  HC1.  It  is  a  2  liter  size.  A 


106  CHEMICAL  ANALYSIS  OF   SPECIAL   STEELS 

smaller  one  does  not  give  enough  pressure.  B  is  filled  with 
anhydrous  calcium  chloride  and  layers  of  cotton.  C  is  simi- 
larly filled  with  pieces  of  stick  KOH.  D  contains  a  saturated 
solution  of  mercuric  chloride,  to  the  depth  of  i  inch,  as  a 
further  guard  against  sulphur.  E  contains  a  i|  inch  layer  of 
cone.  HC1  to  saturate  the  hydrogen  from  A  with  HC1  just 
before  it  enters  F.  The  tube  E  should  be  refilled  every  other 
time  it  is  used.  The  tube  L  is  empty  and  is  used  as  a  trap  for 
tarry  matter,  water  and  acid  coming  from  F.  M  contains  the 
ammoniacal  solution  of  cadmium  chloride  of  the  same  strength 
as  used  -in  ordinary  evolutions.  As  stated  the  total  insoluble 
residue  is  shoved  into  F  which  should  be  nearly  cold  or  at  least 
not  hot  enough  to  cause  hydrogen  to  explode.  The  boat  is 
pushed  into  the  hottest  part  of  F  or  to  the  location  G.  The 
furnace  G  is  the  same  one  as  used  for  carbon  determinations 
with  air  blast  and  gas.  This  type  is  better  adapted  for  this 
work  as  it  will  cool  quickly  and  heat  up  in  a  few  minutes.  Only 
the  shutters  in  the  middle  of  the  furnace  are  opened  as  it  is  not 
desirable  to  heat  the  entire  furnace  for  fear  of  burning  the  rubber 
connection  with  L.  As  soon  as  the  boat  is  in  place  the  stopper 
carrying  E  is  inserted  tightly  into  F  and  the  stream  of  hydrogen 
is  started  through  the  apparatus.  After  the  hydrogen  has 
passed  for  about  20  minutes  the  burner  is  lighted  and  a  suffi- 
cient amount  of  gas  and  air  blast  are  applied  to  bring  the  tube 
up  to  a  yellow  heat  in  about  ten  or  fifteen  minutes.  The  pas- 
sage of  the  gas  at  this  temperature  is  continued  for  a  half  hour. 
Then  the  rubber  connection  with  L  is  pinched  tight  and  a  freshly 
filled  tube  of  the  cadmium  salt  is  substituted  at  M .  The  first 
tube  holds  almost  all  of  the  sulphur;  if  the  conditions  are  just 
right  but  little  sulphide  forms  in  the  2nd  M.  Every  half  hour 
a  fresh  tube  is  put  in  at  M  until  no  further  sulphide  collects  at 
M.  The  various  M  tubes  are  filtered  through  as  in  an  ordinary 
evolution,  beginning  with  the  tube  containing  the  least  sul- 
phide, and  filtering  all  through  the  same  paper. 

The  paper  and  the  adhering  sulphide  are  then  finished  as  in 
plain  steels  as  given  on  pages  269  to  271.    This  gives  the  major 


TUNGSTEN,  SULPHUR,  SILICON,  MANGANESE,  ETC.,  IN  STEELS     107 

part  of  the  sulphur  and  is  added  to  that  obtained  by  the  prelimi- 
nary solution,  to  get  the  total  evolved  sulphur.  In  some  steels 
the  amount  obtained  in  the  preliminary  solution  may  equal  or 
exceed  that  obtained  in  the  heated  tube,  depending  both  on 
the  kind  and  the  amount  of  alloying  element  present. 


STANDARDIZATION  or  THE  APPARATUS  AND  THE  IODINE 
SOLUTION  WITH  BARIUM  SULPHATE. 

The  author  decided  that  the  best  standardization  medium 
would  be  c.p.  barium  sulphate  and  found  that  this  salt  is  ideal 
for  this  work  as  its  sulphur  is  readily  converted  under  the  con- 
ditions to  hydrogen  sulphide.  The  freshly  ignited  salt  is  quickly 
weighed  onto  a  filter  paper  that  has  been  moistened  with  some 
of  the  solution  of  an  alloy  steel  from  which  the  insoluble  resi- 
due has  been  filtered  in  order  to  imitate  as  closely  as  possible 
the  conditions  of  an  ordinary  test.  The  filter  and  the  barium 
sulphate  are  then  put  in  a  clay  boat  and  shoved  into  the  cold 
evolution  tube  and  the  process  is  then  carried  out  as  already  out- 
lined. The  cadmium  sulphide  so  obtained  is  titrated  to  get  the 
sulphur  value  of  the  iodine  standard.  For  the  standardization 
it  is  convenient  to  weigh  0.020  gram  of  the  barium  sulphate.  A 
blank  is  also  put  through  by  moistening  a  filter  paper  with  the 
same  filtrate  as  is  used  in  the  standardizations.  As  Q  check 
standardization,  one  can  use  o.oio  gram  of  the  BaSO4.  The 
blank  is  deducted  and  the  number  of  c.c.  of  the  iodine  required 
to  combine  with  hydrogen  sulphide  evolved  from  the  barium 
salt  is  divided  into  the  sulphur  content  of  the  barium  sulphate 
used.  For  example  suppose  it  is  found  that  a  blank  determina- 
tion put  through  every  operation  consumed  2.4  c.c.  of  iodine 
and  that  0.020  gram  of  the  sulphate  produced  enough  sul- 
phide and  other  products  from  the  filter  and  reagents  to  con- 
sume 25.8  c.c.  Then  since  barium  sulphate  contains  13.73  Per 
cent  sulphur,  0.020  X  0.1373  divided  by  23.4  equals  0.0001173, 
or  i  c.c.  of  the  standard  iodine  equals  0.0001173  gram  of  sulphur 
under  the  conditions  as  given. 


CHAPTER   IV. 

PART  IV. 
ANALYSIS  OF  LOW  PER  CENT  TUNGSTEN  STEELS. 

WHEN  tungsten,  phosphorus  and  silicon  are  wanted  in  steels 
that  contain  from  3.0  to  3.5  per  cent  tungsten  and  less  than  i  per 
cent  chromium,  dissolve  3  grams  in  60  c.c.  of  1.20  nitric  acid 
in  a  No.  5  dish.  Evaporate  to  dryness.  Ignite  to  dull  red. 
Cool  and  dissolve  in  concentrated  hydrochloric  acid,  and  finish 
as  given  under  the  analysis  of  high  chromium-tungsten  steels 
when  silicon  and  phosphorus  are  wanted. 

ANALYSIS  or  ALL  TUNGSTEN  AND  CHROME  STEELS  WHEN 
CHROMIUM  AND  TUNGSTEN,  ONLY,  ARE  ASKED  FOR. 

(Third  Method  for  Tungsten  in  Steel.) 

Dissolve  2  grams  of  sample  in  30  c.c.  i  :  3  sulphuric  acid. 
Heat  until  all  action  is  over.  Add  60  c.c.  1.20  nitric  acid  and 
digest  at  just  below  boiling  until  the  residue  in  the  400  c.c.  beaker 
is  a  clear  yellow  free  of  black  particles.  Dilute  to  200  c.c.  with 
water,  and  boil  for  20  minutes.  Add  some  paper  pulp,  filter, 
and  wash  free  of  iron  test  with  dilute  sulphuric  acid.  Dilute 
the  nitrate  to  500  c.c.  and  mix.  From  this  solution  fill  a  250  c.c. 
flask  to  the  mark. 

First  Portion.  Precipitate  the  remaining  tungstic  acid  from 
this  portion  with  cinchonine.  Wash  it  free  of  iron  test  with 
water  containing  cinchonine  solution.  Ignite  it.  Weigh  and 
fuse  with  twenty  times  its  weight  of  bisulphate  of  potassium. 
Obtain  the  amount  of  pure  W03  as  given  under  bisulphate 
fusion;  see  pages  68  and  101.  Multiply  the  weight  of  W03  by  2. 
Iron  can  also  be  removed  by  sodium  carbonate  fusion.  See 
page  72.  The  main  tungsten  precipitate  is  ignited,  weighed 

108 


ANALYSIS   OF   LOW   PER   CENT  TUNGSTEN   STEELS         109 

and  purified  in  the  same  manner.  The  weight  of  WOs  thus 
obtained  is  added  to  twice  the  weight  of  the  WO3  obtained  by 
the  cinchonine.  This  sum  is  multiplied  by  79.31  and  divided 
by  the  weight  taken  for  analysis  to  obtain  per  cent  of  tungsten. 
Second  Portion.  Finish  this  for  chromium  as  given  under 
determination  of  chromium  in  chromium-vanadium  steel, 
pages  7  and  30.  If  the  chemist  prefers  to  obtain  the  chromium 
by  a  separate  analysis,  he  can  get  the  total  tungsten  by  one 
operation.  The  entire  filtrate  from  the  main  tungsten  residue 
is  precipitated,  without  dividing  it,  by  cinchonine.  This  pre- 
cipitate is  burned  off  with  the  main  residue.  The  combined 
residues  which  constitute  the  total  tungsten  from  2  grams  of 
sample  are  then  freed  from  impurities  in  the  usual  way  with 
bisulphate  or  sodium  carbonate,  and  the  total  weight  of  pure 
WOs  is  multiplied  by  79.31  and  divided  by  the  weight  taken 
for  analysis  to  obtain  the  per  cent  of  tungsten.  If  the  iron 
oxide  is  removed  by  sodium  carbonate  the  silica  is  first  removed 
by  evaporation  with  hydrofluoric  acid  and  sulphuric  acid  as 
given  on  page  72.  The  oxides  are  ignited,  weighed,  and  then 
the  iron  is  removed  by  the  carbonate  fusion. 

CINCHONINE  SOLUTION. 

Dissolve  25  grams  of  cinchonine  in  200  c.c.  of  I  :  i 
hydrochloric  acid. 

Cinchonine  precipitates  tungsten  almost  instantly  from  hy- 
drochloric solution.  It  precipitates  molybdenum  after  consider- 
able lapse  of  time,  and  then  only  partially.  At  least,  the  above 
statement  regarding  molybdenum  is  correct  if  the  attempt  is 
made  in  the  manner  as  given  for  tungsten.  This  constitutes  a 
distinct  difference  between  these  two  elements. 

ANALYSIS  OF  CHROME-TUNGSTEN-VANADIUM  STEELS  FOR 
CHROMIUM  AND  VANADIUM. 

These  elements  are  determined  as  in  chrome-vanadium  steels, 
boiling  with  sufficient  excess  of  permanganate  so  that  the  tung- 


110  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

sten  residue  looks  brown  from  manganese  oxide  after  twenty 
minutes'  boiling.  Filter  on  asbestos  and  finish  as  usual.  (See 
pages  7  and  30.) 

THE  ANALYSIS  OF  CRUCIBLE  SLAG  FROM  TUNGSTEN- 
VANADIUM-CHROMIUM  STEEL. 

Tungsten  Oxide  and  Silica.  Fuse  i  gram  of  the  finely  ground 
slag  with  a  mixture  of  10  grams  of  sodium  carbonate  and  2  grams 
of  potassium  nitrate  in  a  platinum  crucible.  Dissolve  the  melt 
in  a  platinum  dish  in  water  and  transfer  the  solution  and  the 
insoluble  matter  to  a  600  c.c.  casserole;  acidulate  with  an  excess 
of  HC1,  about  75  c.c.;  heat  with  the  cover  on  until  all  effer- 
vescence is  over,  and  evaporate  to  dryness  on  the  graphite; 
heat  with  30  c.c.  of  cone.  HC1  to  dissolve  the  iron;  then  with 
150  c.c.  of  water  to  dissolve  the  sodium  salt;  cool;  add  paper 
pulp;  filter;  wash  with  i  :  40  HC1  until  free  of  iron  test;  hold 
this  residue  (A),  as  the  main  silicic  and  tungstic  acids;  the  fil- 
trate and  washings  from  A  are  again  evaporated  to  dryness; 
dissolved;  filtered  and  washed  as  above;  and  the  residue  on 
the  filter  is  designated  as  B.  The  filtrate  and  washings  from 
B  may  still  contain  a  little  sodium  metatungstate  which  is 
recovered  by  adding  to  the  said  filtrate  and  washings  10  c.c.  of 
cinchonine  solution;  and,  after  stirring  the  same  well,  at  least 
4  hours  are  allowed  to  elapse  before  the  tungsten  cinchonate 
(C)  is  filtered  out;  washed  with  cinchonine  water  and  burned 
off  with  B  and  A.  The  ash  from  A,  B  and  C  contains  all  of  the 
tungsten  and  silica.  The  latter  is  removed  by  evaporation 
with  15  c.c.  of  HF1  and  10  drops  of  cone.  H2S04  and  ignition  at 
a  low  red  heat.  The  difference  between  the  weight  of  the  ash 
from  A,  B,  C,  before  this  evaporation  and  its  weight  after  the 
evaporation  and  ignition,  is  calculated  to  percentage  of  SiO2. 
The  residue  remaining  after  the  evaporation  with  HF1,  etc.  is 
fused  with  about  twenty  times  its  weight  of  sodium  carbonate 
at  a  bright  red  heat  for  a  half  hour,  or  until  all  bubbling  of  CO2 
is  over;  is  dissolved  in  water;  the  insoluble  residue  is  filtered 
out;  thoroughly  washed  free  of  salt;  ignited;  weighed;  and  de- 


ANALYSIS  OF  LOW   PER   CENT   TUNGSTEN   STEELS         III 

ducted  from  the  silica  free  weight  of  A,  B,  C.    The  remainder 
so  obtained  is  figured  to  percentage  of  WOs. 

Oxides  of  Calcium,  Magnesium,  Manganese  and  Iron.  Fuse  i 
gram  of  the  slag  as  above  and  proceed  as  directed  up  to  the 
point  where  the  filtrate  and  washings  from  B  are  obtained  which 
will  contain  all  of  the  Ca,  Mg,  Fe  and  Mn  except  a  small 
amount  remaining  with  the  A  and  B.  Fuse  the  ash  from  A  and 
B  with  sodium  carbonate  as  above,  obtaining  the  water  insol- 
uble residue  which,  after  being  thoroughly  washed,  is  dissolved 
in  HC1  and  added  to  the  main  filtrate  from  B.  A  double  basic 
acetate  separation  of  the  iron  from  the  manganese  in  this  main 
filtrate  is  made  as  directed  on  pages  188  and  189.  On  the  filter, 
after  the  second  basic  acetate  separation,  will  be  the  iron, 
chromium,  and  aluminum,  and  some  V.  In  the  combined 
filtrates  from  the  two  basic  acetate  separations  will  be  the 
manganese,  calcium  and  magnesium,  which  are  separated  and 
determined  in  the  same  manner  as  given  on  page  65  under  the 
heading  " Oxides  of  Manganese,  Calcium,  etc.,"  beginning  at 
the  .stage  where  the  combined  basic  acetate  filtrates  are  made 
distinctly  ammoniacal  and  the  manganese  is  precipitated  with 
ferricyanide  of  iron. 

The  acetates  of  iron,  chromium,  aluminum,  titanium  and  part 
of  the  vanadium,  if  present,  are  ignited  and  weighed  at  constant 
weight  as  Fe2Os  plus  A12O3  plus  Cr2Os  plus  TiO2  plus  some  V2O5. 
These  oxides  are  fused  with  20  times  their  weight  of  sodium  car- 
bonate intimately  ground  with  twice  their  weight  of  potassium  ni- 
trate to  render  the  mixture  of  oxides  soluble  in  acid.  After  keep- 
ing the  melt  in  a  molten  condition  for  15  minutes,  it  is  cooled  and 
dissolved  in  water  and  acidulated  with  an  excess  of  HC1;  heated 
in  the  porcelain  dish  (to  which  the  water  solution  of  the  fusion 
is  transferred  before  the  acidulation  is  made),  until  all  effer- 
vescence is  over;  the  cover  is  removed;  more  acid  is  added,  if 
necessary,  and  all  is  concentrated  until  a  complete  solution  of 
the  oxides  is  effected.  The  solution  is  then  diluted  in  a  volu- 
metric flask  to  500  c.c.  and  250  c.c.  are  converted  into  nitrates 
by  evaporating  twice  to  20  c.c.  with  50  c.c.  additions  of  cone. 


112  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

nitric  acid.  This  nitric  solution  is  analyzed  for  vanadium  as  in 
f erro-vanadium ;  the  vanadium  found  is  calculated  to  ¥265, 
multiplied  by  two  and  deducted  from  the  total  weight  of  the 
Fe2O3  plus  A12O3  plus  Cr2O3,  etc.,  above  mentioned.  The  other 
250  c.c.  are  transferred  to  a  liter  boiling  flask  and  peroxidized 
to  remove  the  chromium  and  any  vanadium  in  the  manner 
described  on  page  23,  beginning  at  the  point  where  the  direc- 
tions read  to  dilute  to  about  300  c.c.,  getting  nitrates  A  and  B 
and  carrying  out  a  third  peroxidation  obtaining  a  nitrate  C, 
or  until  a  filtrate  is  gotten  that  is  free  from  any  yellow  color  of 
chromium.  The  residue  remaining  on  the  filter  after  the  final 
peroxidation  will  contain  all  of  the  iron  except  a  film  of  the  latter 
remaining  in  the  peroxidation  flask.  The  iron  on  the  filter  is 
dissolved  off  with  i  :  i  HC1  and  is  combined  with  the  small 
.portion  recovered  from  the  flask  by  warming  in  it  some  i  :  i 
HC1.  This  total  iron  is  free  of  chromium  and  vanadium  and 
can  be  determined  by  reducing  it  with  tin  chloride  as  in  iron 
ores  or  it  can  be  converted  to  sulphate  and  reduced  with  zinc  or 
aluminum  and  titrated  with  permanganate.  The  combined 
filtrates  A,  B  and  C  contain  all  of  the  Al  and  Cr  in  one-half  of 
the  original  i  gram  weight.  The  Al  can  be  removed  from  the 
combined  filtrates,  after  first  boiling  them  for  ten  minutes  and 
then  adding  i  :  i  HC1  slowly  and  with  rapid  stirring,  until  tur- 
meric paper  no  longer  immediately  changes  to  even  a  faint 
brown  tint  when  dipped  into  the  solution  being  neutralized. 
When  the  turmeric  fails  to  change  at  once  the  solution  is  still 
alkaline  enough  to  prevent  any  redissolving  of  the  aluminum. 
The  aluminum  can  then  be  filtered  out  and  determined  as  given 
on  page  19.  The  filtrate  from  the  aluminum  can  be  reserved 
for  the  chromium  but  the  author  prefers  to  determine  the  chro- 
mium on  a  separate  sample.  The  iron  found  as  above  is  cal- 
culated to  FeO  by  the  factor  1.286  and  multiplied  by  2  being 
one-half  the  sample. 

Chromium  Oxide  and  Vanadium  Oxide.  Fuse  i  gram  of  the 
ground  slag  in  an  iron  crucible  with  8  grams  of  sodium  peroxide; 
dissolve  out  the  fusion  in  water  and  boil  for  ten  minutes  in  a 


ANALYSIS  OF  LOW  PER   CENT  TUNGSTEN  STEELS        113 

casserole;  acidulate  with  150  c.c.  of  i  :  3  sulphuric  acid;  boil 
with  an  excess  of  potassium  permanganate  and  finish  for  chro- 
mium and  vanadium  as  in  steels.  In  order  to  fix  the  proper  blank 
for  the  vanadium  titration  and  to  check  the  chromium  deter- 
mination, 330  mgs.  of  potassium  dichromate  and  60  mgs.  of 
vanadium  pentoxide  of  99.7  per  cent  V  were  fused  in  the  same 
way  as  the  slag  and  put  through  all  of  the  operations.  It  re- 
quired 132.6  c.c.  of  the  double  sulphate  standard  to  react  with 
the  chromium;  therefore  0.330  X  0.3535  divided  by  132.6 
equals  0.00088  gram,  or  the  value  of  the  sulphate  standard  in 
chromium  per  c.c.  The  vanadium  added,  or  60  X  0.997,  equals 
0.0598  gram  of  V2Os.  The  percentage  of  V  in  the  pentoxide 
being  56  per  cent,  there  was  present  in  the  standard  mixture 
0.56  X  0.0598,  or  0.0335  gram,  V;  i  c.c.  of  the  sulphate  equals 
0.00254  gram  of  V;  therefore  it  will  require  13.2  c.c.  of  this 
standard  to  equal  0.0335  gram  of  V.  Now  .by  actual  titration 
17.0  c.c.  of  the  sulphate  were  used  to  obtain  the  blue  end  point  in 
the  second  part  of  the  titration  made  after  the  addition  of  the 
ferricyanide  as  in  steels;  (see  page  40)  hence  the  blank  to  be 
applied  to  the  analysis  of  the  tests  of  the  slag  should  be 
17.00  c.c.  less  13.20  c.c.  or  a  blank  of  3.8  c.c.  A  mixture  of 
380  mgs.  of  K2Cr2O7  and  80  mgs.  of  ¥265  put  through  the  fusion 
and  all  of  the  above  operations  gave  a  chrome  value  of  i  c.c.  of 
the  standard  equals  0.00088  gram  of  Cr  and  a  V  blank  of  4.0  c.c. 
The  average  blank  is,  therefore,  3.9  c.c.  In  this  particular 
slag  by  the  above  method  2.90  per  cent  V  and  a  check  result 
of  2.92  per  cent  V  were  found,  which  multiplied  by  the  factor 
of  1.627  gave  a  value  in  V204  of  4.71  per  cent.  The  chromium 
found,  using  the  above  factor  of  0.00088,  was  11.76  per  cent  Cr 
and  a  check  result  of  n.88  per  cent  Cr  giving  an  average  of 
11.82  which  multiplied  by  the  factor  1.461  equals  17.26,  or  the 
percentage  of  Cr203  in  the  slag. 

Aluminum.  Having  found  the  total  iron  by  doubling  that 
found  in  the  250  c.c.  portion,  it  can  also  be  calculated  to  Fe203; 
to  the  ferric  oxide  add  twice  the  vanadic  oxide  found  in  the 
other  250  c.c.;  to  this  sum  add  the  chromic  acid  found  in  the 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


separate  portion;  deduct  the  total  of  the  three  oxides  from 
the  total  of  the  oxides  of  iron,  chromium,  aluminum  and  vana- 
dium (being  the  portion  of  the  vanadium  that  may  be  carried 
along  with  the  other  oxides)  and  the  remainder  is  calculated 
to  percentage  as  Al20s  plus  any  titanic  oxide  or  phosphoric  acid 
that  may  be  present.  The  aluminum  free  from  any  titanium  can 
be  obtained  by  rendering  the  combined  filtrates  A,  B  and  C  neutral 
to  immediate  reaction  with  turmeric  paper  as  given  on  page  24. 

Phosphoric  Acid.  This  acid  will  be  also  in  the  filtrates  A, 
B  and  C  and  can  be  obtained  therefrom  as  given  on  page  27. 

Manganese  Oxide.  As  previously  stated  the  manganese  is 
separated  from  the  calcium  and  magnesium  by  the  author's 
method  of  precipitating  it  from  the  combined  filtrates  from  the 
basic  acetate  separation  of  the  aluminum,  iron  and  chromium, 
after  rendering  the  combined ,  nitrates  distinctly  ammoniacal. 
After  thoroughly  washing  the  ferricyanide  precipitate  with  am- 
monium nitrate  and  weak  ammonia  wash,  it  is  ashed  in  a  por- 
celain crucible;  dissolved  in  cone.  HC1;  evaporated  to  fumes  with 
40  c.c.  of  i  :  3  sulphuric  acid,  dissolved  by  first  boiling  it  with 
as  little  water  as  possible;  and  heating  further  with  1.20  nitric 
acid.  The  solution  is  then  transferred  to  a  500  c.c.  volumetric 
flask  and  diluted  to  the  mark  with  1.20  nitric  acid.  25  and 
50  c.c.  portions  are  then  analyzed  for  manganese  as  in  steel. 
If  the  manganese  by  this  method  is  found  to  be  in  excess  of 
5.00  per  cent  it  is  more  reliable  to  use  the  method  given  for 
high  manganese  on  page  188,  or  to  analyze  the  above  HC1  solu- 
tion for  manganese  as  given  on  pages  201  and  202.  The  me- 
tallic manganese  so  found  is  calculated  to  MnO  by  multiplying 
it  by  the  factor  1.291. 

ANALYSIS  FOUND. 


Per  cent. 

Per  cent. 

MnO 

7   4"? 

CaO.. 

2  .  27 

FeO 

14    ">3 

MgO 

o  08 

Al2Os   etc 

o  88 

WO3 

I    OO 

Cr2O3 

17    28 

SiO2      

41.78 

V204  

4-71 

CHAPTER  V. 

PART  I. 
MOLYBDENUM  POWDERS. 

CARBON. 

CARBON  is  obtained  by  direct  combustion  in  a  stream  of 
oxygen,  using  the  electric  furnace  with  temperature  between 
900  and  950  degrees  Centigrade.  Decarbonization  takes  about 
a  half  hour.  Use  some  red  lead  when  the  silicon  content  is 
high;  two  grams  of  the  former  per  gram  of  Mo. 

Phosphorus.  If  any  molybdic  acid  separates  out  during  the 
course  of  a  determination  of  phosphorus  as  in  steels,  it  is  certain 
to  carry  phosphorus  out  with  it  as  phospho-molybdic  acid,  in  the 
same  way  that  tungsten  does.  In  such  cases,  dissolve  the  ferro 
or  powder  in  a  mixture  of  equal  parts  of  cone.  HC1  and  HNOs. 
Take  0.813  gram  of  the  sample;  dissolve  it  in  100  c.c.  of  the 
mixture;  heat  until  all  action  is  over;  add  100  c.c.  of  cone. 
HC1;  heat  with  the  cover  on  until  action  is  over  and  evaporate 
to  25  c.c.  Dilute  to  400  c.c.  and  remove  the  bulk  of  the  molyb- 
denum with  H2S.  Filter;  wash;  and  evaporate  the  nitrate  and 
washings  to  20  c.c.  Add  100  c.c.  of  cone,  nitric  acid;  heat  with 
cover  on  until  action  is  over  and  evaporate  to  25  c.c.  Transfer 
to  a  150  c.c.  beaker;  dilute  to  40  c.c.;  boil  with  a  slight  excess 
of  KMnC>4  and  finish  as  in  phosphorus  in  steel. 

SILICON. 

Dissolve  1.5  grams  in  60  c.c.  1.20  nitric  acid.  Add  120  c.c. 
of  i  :  3  sulphuric  acid.  Evaporate  in  a  porcelain  dish  on  graph- 
ite or  sand  bath  to  thick  white  fumes  of  sulphuric  anhydride. 
Cool  and  add  80  c.c.  i  :  i  hydrochloric  acid.  Boil  five  min- 
utes. Cool  again  and  add  50  c.c.  of  water.  Mix  in  some  paper 


Il6  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

pulp  and  filter  on  an  n  cm.  double  ashless  filter.  Wash  free 
from  iron  test  with  i  :  10  hydrochloric  acid.  Then  wash  free 
from  chloride  test  with  distilled  water.  Ignite  in  a  platinum 
crucible  at  the  faintest  red  heat  until  white.  Weigh  and  evap- 
orate with  hydrofluoric  acid  and  a  few  drops  of  sulphuric  acid. 
Ignite  again  at  lowest  visible  redness.  Calculate  the  loss  of 
weight  as  usual  to  silicon. 

MOLYBDENUM. 

First  Method. 

Fuse  0.500  gram  of  finely  ground  powder  with  twenty  times 
its  weight  of  sodium  carbonate  plus  2  grams  of  potassium 
nitrate.  Heat  cautiously  until  the  fusion  is  free  from  black 
particles.  Dissolve  the  melt  in  a  platinum  or  porcelain  dish 
(platinum  preferred)  with  water.  Remove  the  platinum 
crucible  from  the  dish  and  rinse  it  off  carefully,  allowing  the 
washings  to  run  on  the  filter  through  which  the  water  solution  is 
to  be  poured.  Mix  the  water  solution  of  the  fusion  with  a 
little  paper  pulp  and  filter  it  through  the  filter  aforesaid.  Wash 
the  residue  forty  times  with  dilute  sodium  carbonate  water. 
The  residue  on  the  filter  contains  all  of  the  iron  and  copper 
present  in  the  metal,  a  little  platinum  oxide  from  the  crucible, 
and  a  little  molybdenum. 

The  filtrate  and  washings  are  transferred  to  an  800  c.c.  beaker. 
Two  grams  of  tartaric  acid  are  added.  The  solution  is  acidu- 
lated with  sulphuric  acid  in  slight  excess.  The  acidulated  solu- 
tion is  heated  for  twenty  minutes  to  expel  the  major  portion 
of  the  carbon  dioxide.  It  is  then  cooled;  three  drops  of  phenol- 
phthaleine  solution  are  added.  (See  Phosphorus  in  Steel,  p. 
264.)  A  rather  concentrated  solution  of  sodium  hydroxide  is 
added  until  one  drop  produces  a  pink  color.  Next  add  i  :  3 
sulphuric  acid  until  one  drop  causes  the  solution  to  become 
colorless.  Dilute  to  700  c.c.  with  water.  If  the  attempt  be 
made  to  precipitate  molybdenum,  in  too  acid  a  solution,  by 
hydrogen  sulphide,  the  former  is  partially  reduced  to  a  blue 


MOLYBDENUM   POWDERS  117 

oxide  and  partially  precipitated  as  sulphide.  To  avoid  this 
highly  undesirable  condition  it  is  merely  necessary  to  keep  the 
solution  but  very  slightly  acid  until  it  is  well  saturated  with 
H2S.  It  then  turns  to  a  deep  orange  colored  fluid  from  which 
the  molybdenum  is  quickly  precipitated,  by  the  addition  of  6 
or  7  c.c.  of  i  :  3  sulphuric  acid,  as  a  brown  sulphide.  Pass 
the  gas  for  thirty  minutes  longer.  Add  paper  pulp  to  the  beaker, 
mixing  it  well  with  the  sulphide  just  before  passing  the  gas  for 
the  half  hour  as  directed.  In  this  way  the  precipitation  is 
rapid.  The  sulphide  can  be  filtered  and  washed  quickly.  It 
is  washed  with  H2S  water  containing  2  drops  of  i  :  3  sulphuric 
acid  per  500  c.c.  of  wash  water.  Give  the  sulphide  forty  wash- 
ings, permitting  each  washing  to  drain  off  thoroughly  before 
the  succeeding  one  is  applied.  The  sulphide  is  then  roasted 
just  below  redness  in  a  platinum  crucible.  The  contents  of  the 
crucible  can  be  ignited  without  loss  of  molybdenum  trioxide, 
but  the  crucible  must  not  be  allowed  to  exceed  the  faintest 
visible  redness.  The  MoOs  usually  burns  to  a  brownish  white 
residue,  owing  to  traces  of  impurities. 

After  weighing  the  oxide  it  is  extracted  with  i  :  i  ammonia 
(11.50  per  cent)  on  the  water  bath  until  there  remains  but  a 
small  residue,  consisting  of  traces  of  iron  and  some  silica.  This 
is  mixed  with  a  little  paper  pulp,  filtered  and  washed  thoroughly 
with  dilute  ammonia  water.*  It  is  ignited,  weighed,  and  its 
weight  is  deducted  from  the  first  weight  of  the  MoO3.  The 
remainder  is  multiplied  by  66.66  (or  f  X  100)  and  divided  by 
the  weight  taken  for  analysis  to  obtain  the  per  cent  of  molyb- 
denum in  the  sample.  The  filtrate  and  washings  from  the 
sulphide  precipitation  should  always  be  tested  by  passing  H2S 
through  it  for  an  hour  more  to  make  sure  that  no  further  preci- 
pitation of  molybdenum  sulphide  will  occur.  If  the  directions 
as  given  are  carefully  followed,  no  molybdenum  will  be  found 
at  this  point. 

*  If  this  filtrate  and  washings  are  blue  estimate  the  copper  therein  with  KCN 
as  in  steels,  page  150;  calculate  the  copper  found  to  CuO  and  deduct  the  result 
from  the  weight  of  the  impure  MO3. 


Il8  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Second  Method. 

Completely  soluble  molybdenum  can  be  examined  for  molyb- 
denum as  follows:  Dissolve  0.400  gram  of  fine  ground  sample 
in  30  c.c.  of  i.  20  nitric  acid.  Cool  and  add  2  grams  of  tar- 
taric  acid.  Then  add  an  excess  of  ammonia.  Drop  in  i  :  3 
sulphuric  acid  until  the  solution  is  just  faintly  acid.  Dilute  to 
800  c.c.;  precipitate  with  hydrogen  sulphide;  and  finish  for 
molybdenum  as  given  in  the  first  method. 

IRON. 

The  residue  of  iron,  etc.,  remaining  on  the  filter  from  the 
water  solution  of  the  sodium  carbonate  and  niter  fusion  is  dis- 
solved off  with  a  little  hot  i  :  i  hydrochloric  acid.  The  filter 
is  washed  free  from  iron  test.  This  filtrate  and  washings  are 
almost  certain  to  contain  some  molybdenum.  (The  writer  has 
found  molybdenum  with  the  iron,  even  after  it  has  been  fused 
a  second  time  with  sodium  carbonate.)  Add  dilute  ammonia 
to  the  solution  a  drop  at  a  time  until  the  iron  hydroxide  appears. 
Then  add  sulphuric  acid  (1:3)  until  the  iron  precipitate  just 
dissolves.  Dilute  to  300  c.c.  with  water.  Pass  H2S.  The 
small  quantity  of  molybdenum  quickly  separates.  It  is  filtered 
out  and  washed  in  the  same  manner  as  the  main  sulphide  pre- 
cipitate. Ignite  this  sulphide  to  oxide,  weigh  it,  extract  it  with 
ammonia  in  the  same  way  as  the  main  oxide.  Filter  out  the 
insoluble  matter,  and  wash  it  with  dilute  ammonia.  Ignite  it, 
weigh  it,  and  deduct  the  weight  from  the  first  weight;  calculate 
the  remainder  to  Mo,  and  add  it  to  the  principal  part  of  the 
molybdenum  found.  The  filtrate  and  washings  from  the  small 
sulphide  precipitate  contain  all  of  the  iron  which  can  be  deter- 
mined by  evaporation  to  a  small  volume  with  a  slight  excess  of 
potassium  chlorate.  One  or  two  grams  should  suffice.  Then 
add  an  excess  of  i  :  3  sulphuric  acid  and  evaporate  to  thick, 
white  fumes  of  sulphuric  anhydride.  Dilute  with  water.  Re- 
duce with  zinc  oxide  or  metallic  aluminum,  and  finish  by  titra- 
tion  with  permanganate  solution  as  in  the  determination  of 
iron  in  ferro- vanadium.  (See  page  28.) 


MOLYBDENUM  POWDERS  119 

TUNGSTEN. 

Evaporate  the  filtrate  and  washings  from  the  main  sulphide 
precipitate  obtained  by  the  first  method  to  moist  dryness.  Add 
100  c.c.  of  cone,  nitric  acid.  Heat  with  cover  on  until  all  action 
is  over.  Remove  the  watch  glass  from  the  casserole  and  evap- 
orate again  to  moist  dryness.  Add  water;  heat  until  all  salt 
is  in  solution;  filter  out  the  insoluble  residue;  wash  it  free  from 
salts  with  i  :  20  hydrochloric  acid.  This  will  take  about  forty 
to  fifty  washings.  Evaporate  the  filtrate  and  washings  again 
to  moist  dryness,  and  add  100  c.c.  of  cone,  hydrochloric  acid. 
Heat  with  the  cover  on  as  before,  and  evaporate  a  third  time. 
Add  water;  heat;.*  filter;  wash  with  i  :  20  hydrochloric  acid, 
and  add  the  washed  residue  to  the  first  one  obtained  after  evapo- 
rating with  nitric  acid.  Ignite  and  weigh  as  WOs  +  SiOz. 
Finish  as  given  for  tungsten  in  steels. 

SULPHUR. 

Fuse  2  grams  with  20  grams  of  sodium  carbonate  and  4  grams 
of  potassium  nitrate.  The  fluxes  are  ground  thoroughly  to- 
gether in  an  agate  mortar.  Heat  until  the  melt  is  a  clear  light 
yellow,  free  of  black  specks.  This  requires  but  a  few  minutes. 
Dissolve  the  melt  in  water.  Transfer  it  to  a  casserole.  Acid- 
ulate with  concentrated  hydrochloric  acid,  and  evaporate  to 
dryness  on  the  water  bath.  Add  40  c.c.  of  i  :  i  hydrochloric 
acid.  Heat  with  the  cover  on  for  a  half  hour.  Add  water  and 
heat  again.  Filter  and  wash  with  i  :  20  hydrochloric  acid, 
forty  times.  Heat  the  filtrate  to  boiling,  and  precipitate  with 
barium  chloride  solution,  adding  the  latter  in  excess,  about 
50  c.c.  of  the  saturated  solution.  Considerable  molybdenum 
is  precipitated  with  the  barium  sulphate.  Filter,  washing  with 
water,  only,  until  free  from  chloride  test  to  insure  removal  of  the 
excess  of  BaCl2.  Plug  the  end  of  the  funnel  with  a  rubber  cap 

*  Add  20  c.c.  of  cinchonine  solution;  warm  for  a  short  time  to  permit  the 
precipitate  to  settle;  wash  it  with  a  mixture  of  50  c.c.  HC1,  400  c.c.  of  water  and 
5  c.c.  of  the  cinchonine  solution.  Read  also  page  125. 


120  CHEMICAL  ANALYSIS   OF   SPECIAL   STEELS 

and  fill  it  three-fourths  full  with  i  :  i  ammonia  water  (11.50  per 
cent)  and  keep  covered  for  four  hours,  or  longer  if  convenient. 
Then  allow  this  fluid  to  drain  off,  and  wash  the  residue  with  the 
i  :  i  ammonia  until  10  c.c.  of  the  washings  on  being  acidulated 
in  a  254  by  25.4  mm.  tube  with  hydrochloric  acid,  brought 
just  to  a  boil  with  granulated  tin  (Do  hot  continue  to  boil. 
See  Qualitative  Mo  Test,  page  2),  cooled  to  room  temperature 
and  treated  with  i  or  2  c.c.  of  KCNS  solution,  give  no  reddish 
coloration  due  to  molybdenum.  Ignite  and  weigh  as  BaSO4  as 
in  steels.  Deduct  a  blank.  It  is  always  safer  to  fuse  this  BaS04 
with  sodium  carbonate;  dissolve  the  fusion  in  water;  filter  it; 
acidulate  it  with  hydrochloric  acid;  and  reprecipitate  it  with 
barium  chloride  as  described  under  gravimetric  sulphur  in  steels, 
page  275. 

Even  with  all  of  the  foregoing  precautions,  the  author  has 
found  still  2  or  3  mgs.  of  Mo  in  the  BaSO4.  To  correct  for  the 
Mo,  fuse  the  impure  BaSO4  with  20  times  its  weight  of  Na2CO3; 
dissolve  the  melt  in  water;  filter  out  the  barium  carbonate 
formed;  wash  20  times  with  water;  add  a  few  drops  of  methyl 
orange  to  the  filtrate  and  washings;  then  add  i:  i  HCl  until  i 
or  2  drops  of  the  acid  turn  the  solution  pink;  then  pass  H2S 
until  the  small  precipitate  of  molybdenum  sulphide  separates  out 
well;  wash  the  sulphide  with  H2S  water  until  free  of  chlorides; 
ignite  it  at  the  faintest  redness;  weigh  it;  and  deduct  the  weight 
from  that  of  the  impure  BaSO4  and  calculate  the  remainder,  as 
usual,  to  sulphur. 

MANGANESE. 

Proceed  as  in  steels  or  ferro-vanadium,  dissolving  the  powder 
in  1.20  nitric  acid. 

COPPER. 

Nitric  acid  solutions  of  molybdenum  are  precipitated  but 
slightly,  even  after  one  hour's  standing,  by  potassium  ferri- 
cyanide.  This  reagent  affords  a  rapid  means  of  determining 
the  amount  of  copper  that  may  be  present  in  the  molybdenum. 
Dissolve  i  gram  of  sample  in  30  c.c.  1.20  nitric  acid.  Add 


MOLYBDENUM   POWDERS 


121 


ammonia  until  the  iron  hydroxide  forms.  Then  add  sulphuric 
acid  (i  13)  a  few  drops  at  a  time  until  the  hydrate  of  iron  is 
just  dissolved.  Now  precipitate  the  copper  with  20  c.c.  of  the 
same  potassium  ferricyanide  solution  used  to  separate  copper 
in  ferro- vanadium.  (See  page  149.)  If  the  copper  in  solution 
is  likely  to  exceed  10  mgs.,  then  add  an  additional  2  c.c.  of  the 
ferricyanide  solution  for  every  milligram  of  copper  in  excess  of 
10  mgs.  Finish  as  given  in  the  author's  method  for  copper  in 
steel,  page  149.  The  analysis  of  ferro-molybdenum  is  similar  to 
that  of  the  powders. 

TYPICAL  ANALYSES. 


Carbonless. 

Carbon 

Per  cent. 
A  60 

Per  cent. 
O   O7 

Manganese   . 

o  03 

o  18 

Phosphorus  . 

O   O2O 

O   O^Q 

Sulphur  

I    O2 

Silicon  

O    <?O 

2  88 

Molybdenum  

GO   OO 

02  ?o 

CHAPTER  V. 

PART  II. 
THE  ANALYSIS  OF  FERRO-MOLYBDENUM. 

DISSOLVE  0.4  and  0.5  gram  for  a  check  in  50  c.c.  of  1.20  nitric 
acid  to  a  clear  solution.  Dilute  to  200  c.c.;  add  a  consider- 
able excess  of  i  :  i  ammonia  and  precipitate  the  iron.  Redis- 
solve  this  iron  in  50  c.c.  of  i  :  i  HC1;  reprecipitate  the  iron 
again,  washing  as  before  with  dilute  ammonia  wash.  The  iron 
hydroxide  is  dried;  ignited;  and  weighed  as  Fe203  +  some 
MoO3  and  a  little  Si02.  The  residue  in  the  crucible  is  dissolved 
in  HC1;  the  silica  is  filtered  out;  washed;  weighed  and  deducted 
from  the  total  weight  of  the  oxides  of  iron,  etc.  The  filtrate  from 
the  silica  is  made  nearly  neutral  and  the  molybdenum  therein 
is  precipitated  with  H2S  in  hot  solution;  filtered  out;  washed 
with  H2S  water;  ignited  at  a  very  low  red  heat;  weighed  and 
deducted  from  the  iron  oxide,  etc. ,  giving  a  remainder  consisting 
of  Fe20s  plus  any  phosphoric  acid  that  may  have  been  carried 
out  with  the  iron  oxide.  This  phosphoric  acid  can  be  found  by 
evaporating  the  filtrate  from  the  above  molybdenum  sulphide 
to  low  volume;  convert  to  nitrates  and  finish  the  phosphorus 
as  in  steels.  The  phosphorus  so  found  is  calculated  to  P2Os 
and  deducted  from  the  weight  of  the  P2C>5  plus  F203,  leaving  a 
remainder  that  can  be  calculated  to  metallic  iron.  This  phos- 
phorus is  not  necessarily  the  total  phosphorus.  The  latter  can 
be  determined  on  a  separate  portion  as  described  under  Phos- 
phorus in  Molybdenum  Powder. 

The  main  portion  of  the  molybdenum  is  contained  in  the  two 
sets  of  filtrates  and  washings  from  the  precipitation  and  the 
reprecipitation  of  the  iron  by  ammonia  as  given  above.  These 
filtrates  and  washings  are  combined;  made  slightly  acid  with 
HC1  and  the  Mo  is  separated  with  H2S;  washed;  ignited  and 

122 


THE  ANALYSIS   OF  FERRO-MOLYBDENUM  123 

weighed  as  MoO3  plus  any  little  silica  present  which  is  removed 
by  dissolving  the  MoO3  in  cone,  ammonia  and  warming  until 
only  a  small  floating  residue  remains  which  is  filtered  out; 
washed  with  ammonia  water;  ignited;  weighed;  and  deducted 
from  the  first  weight  of  the  main  MoO3.  The  remainder  plus 
the  Mo03  found  with  the  iron,  as  already  described,  constitutes 
the  total  Mo03  which  is  calculated  to  Mo  by  the  factor  0.6666. 

Silicon.  This  element  can  be  determined  on  the  same  por- 
tion as  is  used  for  the  molybdenum  if  the  nitric  acid  solution 
is  taken  to  dryness  on  the  graphite  bath.  Do  not  ignite  the 
dish  over  a  bare  flame  as  in  tungsten  as  there  is  danger  of  loss 
of  the  Mo  by  volatilization.  Dissolve  the  dry  residue  in  50  c.c. 
or  more,  if  necessary,  of  cone.  HC1;  dilute;  filter;  wash  with 
dilute  HC1;  wash  until  the  residue  on  the  filter  no  longer  gives 
a  test  for  iron;  evaporate  the  filtrate  and  washings  again  to 
dryness;  dissolve;  filter;  wash  as  before;  combine  the  two 
filters  from  the  first  and  second  evaporations;  ignite  the  same 
at  a  very  low  red  heat  and  weigh  as  SiO2  plus  a  little  MoO3. 
For  close  work  this  silica  should  be  fused  with  10  times  its 
weight  of  sodium  carbonate;  the  fusion  dissolved  in  HC1  and 
evaporated  twice  to  dryness  as  before,  finally  weighing  as  pure 
sib'ca.  The  filtrate  from  the  second  evaporation  to  dryness  in 
the  presence  of  the  main  iron  and  Mo  can  be  combined  with 
the  filtrate  and  washings  from  the  evaporation  of  the  acid- 
ulated sodium  carbonate  fusion  of  the  impure  silica.  The 
combined  filtrates  contain  the  total  iron  and  Mo  and  can 
be  analyzed  for  these  elements  as  already  given  under  Ferro- 
Molybdenum. 

The  carbon,  manganese  and  tungsten  are  determined  as  given 
for  Molybdenum  Powders. 

RESULTS  OBTAINED  ON  A  HIGH  CARBON  TYPE. 


Per  cent. 

Per  cent. 

Carbon  

3.66 

Silicon  

o  86 

Manganese  

o.  13 

Iron  

21    26 

Phosphorus  

0.035 

Molybdenum  

71    3O 

124  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

THE  ANALYSIS  or  FERRO-MOLYBDENUM-TUNGSTEN. 

Tungsten,  Phosphorus  and  Silicon.  Dissolve  i  gm.,  and  ij 
gms.  for  a  check,  in  50  c.c.  of  1.20  nitric  acid  in  a  No.  5  porcelain 
dish;  evaporate  dry  but  do  not  ignite  with  a  bare  flame.  Re- 
dissolve  with  ico  c.c.  of  cone.  HG1;  evaporate  dry;  dissolve 
in  50  c.c.  of  cone.  HC1  and  evaporate  to  20  c.c.;  add  25  c.c. 
of  water;  heat  20  minutes;  filter;  wash  with  i  :  40  HC1;  evap- 
orate the  filtrate  and  washings  to  10  c.c.;  add  25  c.c.  of  water; 
heat  and  filter  out  any  small  residue  of  tungstic  acid  that  may 
have  separated  out  after  this  second  evaporation.  The  filtrate 
and  washings  from  this  last  evaporation  are  taken  to  40  c.c.  in 
a  150  c.c.  beaker;  heated  to  near  boiling;  removed  from  the 
fire  and  50  c.c.  of  molybdate  solution  are  added  to  precipitate 
the  phosphorus  which  is  then  finished  as  in  tungsten  steel.  (See 
page  100.) 

The  residues  on  the  filters  from  the  above  first  and  second 
evaporations  to  dryness  contain  all  of  the  tungsten,  silcon  and 
a  little  of  the  molybdenum.  These  papers  are  ignited  at  a  low 
red  heat  until  the  carbon  is  gone;  add  10  grams  of  anhydrous 
sodium  carbonate  to  the  ash  and  fuse  to  a  clear  liquid  that 
no  longer  gives  off  any  bubbles  of  CCV  Dissolve  out  this  fusion; 
acidulate  it  with  HC1  and  evaporate  to  dryness,  after  all  effer- 
vescence and  spraying  are  over,  in  the  covered  casserole.  If  the 
fusion  is  dissolved  out  in  porcelain,  the  solution  must  be  made  acid 
with  HC1  as  the  dissolving  of  carbonate  fusions  with  water  alone 
in  porcelain  dishes  causes  the  latter  to  be  attacked  and  silicon  re- 
sults to  be  too  high,  especially  if  heat  is  applied  to  hasten  matters. 

After  the  evaporation  to  dryness  the  residue  is  redissolved 
in  HC1;  add  water;  filter  out  the  tungsten;  wash  it  as  before; 
evaporate  the  filtrate  and  washings  again  to  dryness;  dissolve; 
filter;  and  wash.  This  second  filtrate  and  washings  will  con- 
tain some  tungsten  which  must  be  removed  by  cinchonine; 
heat  the  filtrate  before  adding  the  cinchonine;  filter  out  the 
tungsten  so  precipitated;  wash  it  with  cinchonine  water;  com- 
bine this  filter  with  the  two  residues  obtained  from  the  evap- 


THE  ANALYSIS  OF   FERRO-MOLYBDENUM  125 

oration  of  the  above  fusion  twice  to  dryness  and  burn  all  in  a 
platinum  crucible  to  a  yellow  residue  free  from  the  carbon  of 
the  niters;  weigh  it  as  WO3  +  SiOz-  Remove  the  silicon  by  the 
usual  evaporation  with  HF1  and  H2SO4,  calculating  the  loss  of 
weight  as  the  silicon  of  the  alloy.  The  residue  in  the  crucible  is 
calculated  to  tungsten  by  the  factor  0.7931. 

Molybdenum.  Fuse  0.5  gram  of  the  finely  ground  alloy  in  a 
platinum  crucible  with  an  intimate  mixture  of  10  grams  of 
sodium  carbonate  and  0.5  gram  of  niter  until  a  quiet  fusion  is 
obtained  and  then  continue  to  maintain  the  fusing  temperature 
for  10  minutes  more.  Dissolve  the  fusion  out  in  water;  filter 
out  the  insoluble  residue  of  iron  and  manganese;  wash  it  with 
sodium  carbonate  water;  ignite  it;  grind  it  in  a  small  agate 
mortar;  return  the  fine  powder  again  to  the  crucible;  clean  the 
mortar  by  grinding  it  out  with  a  little  sodium  carbonate ;  return 
this  carbonate  to  the  crucible;  again  grind  some  fresh  carbonate 
in  the  mortar,  and  so  on  until  the  carbonate  no  longer  shows  a 
change  of  color  when  ground  in  the  mortar.  Grind  10  grams  of 
carbonate  with  0.200  gram  of  niter  for  this  second  fusion  which 
is  made  and  dissolved  out  as  in  the  first  fusion.  The  filtrates 
and  washings  from  insoluble  residues  obtained  after  each  fusion 
contain  all  of  the  molybdenum  and  tungsten  from  the  alloy. 
The  first  filtrate  and  washings  contain  practically  all  of  these 
elements.  Add  to  it  2  grams  of  tartaric  acid  and  2  drops  of 
methyl  orange  solution  (i  gram  of  the  methyl  orange  dissolved 
in  a  liter  of  water) .  Now  add  HC1  until  one  drop  just  turns  the 
solution  pink.  Pass  H2S  through  the  solution  when  it  will  turn 
a  deep  red  due  to  the  combination  with  the  H2S;  the  addition 
of  a  few  drops  of  HC1  will  cause  the  molybdenum  sulphide  to 
then  precipitate  out  promptly  and  perfectly  after  a  thorough 
saturation  with  H2S.  The  directions  must  be  carefully  followed 
for  if  the  attempt  is  made  to  precipitate  molybdenum  from  a 
solution  containing  much  free  acid,  a  blue  filtrate  is  obtained 
which  contains  much  of  the  molybdenum  in  a  reduced  form 
that  is  very  unsatisfactory  to  handle,  as  explained  on  page  131. 
Wash  the  molybdenum  sulphide,  so  obtained  from  both  sets  of 


126  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


filtrates  and  washings,  thoroughly  with  HaS  water  ;  ignite  it  at  a 
low  red  heat  and  weigh;  dissolve  this  MoO3  in  ammonia;  filter 
the  solution;  wash  the  filter  thoroughly  with  ammonia;  ignite 
it  ;  weigh  it;  deduct  this  weight  from  the  first  weight  of  the  MoO3 
and  calculate  the  difference  in  weight  to  molybdenum  by  the  use 
of  the  factor  0.6666. 

Iron,  The  insoluble  residue  obtained  from  the  second  fusion 
with  sodium  carbonate  and  niter  contains  all  of  the  iron  free 
from  tungsten  and  Mo  and  is  especially  convenient  for  the  iron 
determination  as  the  two  latter  elements  must  be  separated 
before  the  iron  can  be  determined.  Dissolve  this  residue,  after 
burning  off  the  paper  in  the  crucible  in  which  the  fusion  was 
made,  in  cone.  HC1;  clean  the  iron  stains  from  the  crucible 
with  this  acid;  precipitate  the  solution  of  the  residue  and  the 
cleanings  of  the  crucible  with  ammonia;  redissolve;  reprecip- 
itate,  and  redissolve  it  again  to  remove  any  platinum;  then 
reduce  the  solution  with  stannous  chloride  and  finish  for  iron 
as  in  iron  ore  by  titration  of  the  reduced  iron  with  potassium 
dichromate.  (See  page  367.) 

Sulphur.  Heat  2  grams  and  3  grams  for  a  check,  of  the 
powdered  sample  or  drillings  with  200  c.c.  of  cone.  HNOs  in  600  c.c. 
beakers  until  red  fumes  are  gone;  add  100  c.c.  of  HC1  and  heat 
until  all  action  is  over  and  the  insoluble  portion  is  of  a  clear  yellow 
color;  transfer  the  solution  to  a  casserole;  add  2  grams  of  Na2C03 
and  evaporate  to  dryness;  do  not  ignite;  add  20  c.c.  of  cone.  HC1; 
and  heat  until  the  insoluble  matter  is  flotant;  add  150  c.c.  of  water, 
and  heat  further;  filter  and  wash  with  HC1  water;  evaporate 
the  filtrate  and  washings  again  to  dryness;  redissolve;  dilute; 
filter;  and  wash  as  before;  precipitate  the  iron  from  the  filtrate 
and  washings  with  a  slight  excess  of.  ammonia;  filter  out  the 
iron  hydroxide  and  wash  it  with  water;  dilute  the  filtrate  and 
washings  from  the  iron  to  300  c.c.;  add  enough  HC1  to  this 
filtrate  and  washings  to  just  neutralize  it,  and  then  an  excess 
of  20  c.c.  of  cone.  HC1;  dilute  with  water  to  400  c.c.;  heat  to 
boiling;  add  25  c.c.  of  a  saturated  solution  of  barium  chloride; 
let  the  solution  stand  12  hours.  Filter  off  the  barium  sulphate 


THE  ANALYSIS  OF   FERRO-MOLYBDENUM 


I27 


which  is  almost  certain  to  contain  considerable  molybdenum. 
Wash  this  precipitate  with  water  only;  ignite  it  at  a  low  red 
heat  in  a  platinum  crucible;  moisten  it  with  a  drop  or  two  of  sul- 
phuric acid  to  convert  any  barium  sulphite  formed  by  the  re- 
ducing action  of  the  burning  filter  paper;  fuse  this  residue  of 
barium  sulphate  and  some  Mo  with  i  gram  of  sodium  carbonate ; 
dissolve  the  melt  in  water;  filter  out  the  barium  carbonate; 
wash  the  filter  thoroughly  with  water  containing  5  grams  of 
sodium  carbonate  to  500  c.c.  of  water.  Add  to  the  filtrate  and 
washings  2  drops  of  methyl  orange;  then  HC1  until  the  solution 
just  turns  pink;  then  add  an  excess  of  40  c.c.  of  i  :  i  HC1  and 
dilute  to  400  c.c.  with  water.  Heat  to  boiling  and  precipitate, 
as  before,  the  sulphur  present  as  barium  sulphate.  Finish  from 
this  point  as  given  on  page  120.  Blanks  should  be  run  cover- 
ing all  operations  and  any  sulphur,  so  found,  deducted. 

The  carbon  and  manganese  can  be  determined  as  in  tungsten 
powder. 

ANALYSIS  FOUND. 


Per  cent 

Per  cent 

Carbon  

1.84 

Tungsten 

IO   O2 

Manganese 

O    32 

M^olybdenum 

42  66 

Phosphorus  . 

o  086 

Iron 

4.2    1  2 

Silicon  

i  8=; 

Sulphur 

O    14. 

CHAPTER  V. 

PART  III. 
THE  DETERMINATION  OF  MOLYBDENUM  IN  MOLYBDENITE  ORE. 

THE  finely  ground  sample  is  heated  for  a  time  with  100  c.c.  of 
cone.  HC1;  and  then  with  the  addition  of  4  grams  of  potassium 
chlorate,  in  2  gram  portions,  until  the  smell  of  chlorine  is  gone. 
Add  150  c.c.  of  water,  filter  and  wash.  The  free  acid  in  the 
filtrate  must  be  neutralized  with  i  :  i  ammonia.  Pass  H2S  until 
the  molybdenum  sulphide  settles  well  in  hot  solution.  Filter  out 
the  sulphide  and  wash  it  with  H2S  water  containing  a  drop  or 
two  of  i  :  i  HC1.  The  molybdenum  sulphide  obtained  at  this 
point  is  dried  and  retained. 

The  filtrate  and  washings  from  the  sulphide  are  tested  with 
more  H2S  but  none  will  be  found  if  the  conditions  are  correct, 
that  is,  the  Mo  should  be  precipitated  from  as  nearly  neutral  a 
solution  as  possible.  The  insoluble  residue  from  the  original 
treatment  with  HC1  and  chlorate  is  burned  off  in  a  30  c.c.  plat- 
inum crucible  at  a  very  low  red  heat  and,  when  the  carbon  of  the 
paper  is  all  gone,  the  ash  is  fused  with  10  grams  of  sodium  car- 
bonate. Dissolve  the  fusion  in  a  600  c.c.  casserole  with  80  c.c. 
of  cone.  HCL  Clean  the  crucible  with  a  little  HC1  and  take  the 
total  solution  to  dryness.  Redissolve  by  first  heating  with  20  c.c. 
of  cone.  HC1;  add  150  c.c.  of  HC1;  filter  off  the  silica;  wash  with 
dilute  HC1  wash;  evaporate  the  filtrate  and  washings  again  to  dry- 
ness;  take  up;  filter;  wash  as  before;  pass  H2S  through  this  last 
filtrate  and  washings  to  get  the  remainder  of  the  molybdenum. 
Filter  out  the  molybdenum  found  here;  wash  it  as  in  the  first 
precipitation;  and  combine  it  with  the  Mo  found  in  the  first  in- 
stance. Test  the  filtrate  and  washings  from  this  second  H2S  pre- 
cipitation to  make  sure  that  all  of  the  Mo  has  been  precipitated. 

The  total  sulphides  of  Mo  are  then  burned  at  a  very  low  red 
heat  and  finished  as  in  molybdenum  in  steel. 

128 


CHAPTER  V. 

PART  IV. 
METHOD  FOR  TUNGSTEN  AND  MOLYBDENUM  STEELS. 

ABSENCE  or  MOLYBDENUM. 
(Second  Method  for  Tungsten  in  Steel.) 

DISSOLVE  2  grams  of  steel  in  a  mixture  of  30  c.c.  of  concen- 
trated nitric  acid  and  30  c.c.  of  1.20  specific  gravity  hydro- 
chloric acid  in  a  No.  5  porcelain  dish.  Keep  at  a  digesting  heat 
until  the  tungstic  acid  is  a  bright  yellow.  Agitate  the  solution 
frequently  by  stirring  the  sediment  vigorously,  but  do  not  leave 
glass  rods  in  the  hot  acid.  Remove  the  former  after  each  stir- 
ring, as  tungstic  acid  attacks  glass  in  hot  acid  solution,  causing 
silicon  results  to  be  too  high.  When  the  tungstic  acid  is  a  clear 
yellow  remove  the  lid  and  evaporate  to  20  c.c.  volume.*  Now 
add  100  c.c.  of  distilled  water.  Stir  thoroughly.  Remove 
stirring  rod.  Heat  to  incipient  boiling  for  at  least  a  half  hour. 
Filter,  adding  ashless  paper  pulp.  Wash  with  i  :  20  hydro- 
chloric acid  until  free  of  iron  test.  Ignite  and  weigh  as  WOs  + 
SiC>2  +  Fe20a.  Evaporate  with  hydrofluoric  and  sulphuric  acids 
as  described  on  page  72.  Weigh  as  WO3  +  Fe2O3.  The  loss  of 
weight  here  is  part  of  the  total  silicon.  This  is  the  most  rapid 
of  the  three  methods  for  tungsten  in  steel. 

Fuse  the  WOs  +  Fe2Os  with  5  grams  of  sodium  carbonate 
until  molten.  Keep  molten  for  20  minutes.  Dissolve  in  a 
casserole  with  distilled  water.  Filter  out  the  small  residue  of 

*  At  this  point,  in  order  to  insure  the  complete  removal  of  the  nitric  acid,  it 
is  better  to  carry  this  evaporation  further  until  moist  dryness  is  attained;  then 
add  50  c.c.  of  cone.  HC1  and  evaporate  to  10  c.c.,  heating  with  the  cover  on  the 
vessel,  in  case  red  fumes  form  on  introducing  the  50  c.c.,  until  all  danger  of  loss 
from  spraying  is  over.  Then  evaporate  to  10  c.c.  as  directed.  "Now  add  100 
c.c.  of  distilled  water,"  etc. 

129 


130  CHEMICAL  ANALYSIS  OF  SPECIAL   STEELS 

iron  and  wash  it  with  water  until  free  of  carbonate.  About 
forty  washings  will  suffice.  Ignite  this  residue  in  a  weighed 
crucible,  and  deduct  its  weight  from  the  weight  of  WO3  +  Fe2O3. 
The  remainder  is  the  pure  W03,  which,  multiplied  by  79.31  and 
divided  by  the  weight  taken  for  analysis,  yields  the  per  cent  of 
tungsten.  Read  page  72  concerning  iron  in 


SILICON  AND  PHOSPHORUS. 

If  silicon  and  phosphorus  are  asked  for,  evaporate  the  nitrate 
and  washings  from  the  tungstic  acid  to  10  c.c.  Add  50  c.c. 
cone,  nitric  acid  and  evaporate  again  to  10  c.c.  Add  50  c.c. 
more  of  cone,  nitric  acid  and  evaporate  to  hard  dryness.  Ignite 
to  dull  red,  and  proceed  as  given  on  page  99  for  the  balance  of 
the  silicon  and  for  the  phosphorus. 

IN  THE  PRESENCE  OF  MOLYBDENUM. 

Proceed  as  in  the  absence  of  molybdenum  to  the  point  where 
the  nitrate  and  washings  from  the  tungstic  acid  have  been 
obtained.  Transfer  the  fluid  to  a  500  c.c.  flask.  Dilute  to 
the  mark  with  water.  Mix  thoroughly,  and  from  this  quanti- 
tatively fill  a  250  c.c.  flask. 

Finish  one  portion  for  phosphorus  and  silicon  as  given  in  the 
absence  of  molybdenum.  Calculate  the  phosphorus  on  the 
basis  of  one-half  the  original  weight  taken  for  analysis,  that  is, 
as  though  i  gram  were  taken.  The  silicon  obtained  from  this 
portion  is  multiplied  by  2  and  added  to  that  obtained  from 
the  tungstic  oxide.  The  total  is  calculated  on  a  2  gram  basis. 

The  tungstic  oxide,  which  always  contains  a  little,  and  some- 
times much,  molybdic  oxide,  is  ignited  at  the  faintest  red  heat 
until  yellow;  weighed;  the  silica  is  removed  from  it  by  evapo- 
rating with  hydrofluoric  and  a  little  sulphuric  acid.  The  residue  is 
then  ignited  at  the  lowest  possible  heat  and  weighed  again.  The 
loss  of  weight  at  this  point  is  the  silica  that  remained  with  the 
tungstic  oxide. 

The  remainder  is  the  W03  plus  some  Mo03  and  Fe2O3.  The 
combined  oxides  are  fused  with  10  grams  of  sodium  carbonate 


METHOD   FOR  TUNGSTEN  AND  MOLYBDENUM  STEELS     131 

for  a  half  hour  at  a  red  heat  with  a  Bunsen  burner.  The  melt 
is  dissolved  in  water;  the  iron  is  filtered  out  and  washed  with 
water.  It  is  ignited;  weighed;  and  the  weight  is  deducted. 
The  filtrate  and  washings  are  treated  with  2  grams  of  tar- 
taric  acid;  are  acidulated  very  slightly  with  sulphuric  acid; 
and  the  molybdenum  is  separated  with  H2S.  The  MoS3  is 
ignited  to  oxide,  and  the  weight  of  the  oxide  is  deducted  from 
the  weight  of  W03  +  Mo03.  The  remainder  is  multiplied  by 
79.31  and  divided  by  the  weight  taken  for  analysis  to  obtain 
the  percentage  of  tungsten.  See  the  directions  for  the  precipi- 
tation of  molybdenum  as  sulphide,  given  below. 

As  molybdic  oxide  sublimes  at  a  bright  red  heat,  hence  the 
repeated  caution  not  to  ignite  either  it  or  the  sulphide  above  the 
faintest  suggestion  of  redness.  A  slight  white  fume  rising  in 
the  crucible  when  heating  the  oxide  at  redness  indicates  loss  of 
the  latter.  The  MoO3  found  with  the  tungstic  oxide  is  calculated 
to  Mo  multiplying  by  0.6666.  This  amount  is  added  to  twice  the 
weight  of  Mo,  in  parts  of  a  gram,  found  in  the  second  250  c.c.  por- 
tion. The  total  is  multiplied  by  100  and  divided  by  2  to  obtain 
the  total  per  cent  of  molybdenum  in  the  two  gram  sample. 

The  principal  part  of  the  molybdenum,  obtained  in  the  second 
half  of  the  divided  filtrate,  is  separated  as  follows:  Add  ammonia 
to  it  until  a  precipitate  forms  that  no  longer  dissolves  on  stirring. 
Add  i  :  3  sulphuric  acid  until  this  precipitate  just  dissolves. 
Then  saturate  the  nearly  neutral  solution  with  hydrogen  sul- 
phide, and  obtain  the  molybdenum  in  this  half  of  the  divided 
filtrate.  If  the  solution  containing  the  molybdenum  is  too 
nearly  neutral,  H2S  causes  only  a  deep  red  coloration  in  it;  if 
the  solution  is  too  acid,  the  passage  of  the  hydrogen  sulphide 
results  in  a  partial  precipitation  of  the  molybdenum  together 
with  a  blue  coloration.  From  the  red  solution  the  molybdenum 
is  easily  precipitated  by  a  very  slight  addition  of  acid.  Add  the 
latter  cautiously,  a  c.c.  or  two  at  a  time,  until  the  molybdenum 
begins  to  settle  rapidly.  Then  pass  H2S  a  little  while  longer. 
If  the  H2S  has  been  passed  through  too  acid  a  solution  of  molyb- 
denum, with  the  resulting  partial  precipitation  giving  a  blue 


132  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

filtrate,  the  best  thing  to  do  is  to  begin  the  analysis  over,  giving 
proper  attention  to  these  details.  The  molybdenum  can  be 
completely  precipitated,  if  the  conditions  are  observed  as  here 
given,  in  a  half  hour's  time  with  a  rapid  stream  of  H2S. 

VOLUMETRIC  DETERMINATION  OF  MOLYBDENUM  IN  STEEL. 

After  weighing  the  molybdenum  as  oxide,  the  results  so  ob- 
tained can  be  checked  as  follows:  Fuse  the  oxide  with  5  grams 
of  carbonate  of  soda.  Dissolve  the  melt  in  about  50  c.c.  of 
water  in  a  dish.  Filter  the  solution  on  a  7  cm.  filter.  Wash 
the  latter  thoroughly  with  sodium  carbonate  water.  Evaporate 
the  filtrate  and  washings  to  50  c.c.  Acidulate  with  i  :  3  sul- 
phuric acid,  adding  an  excess  of  100  c.c.  Next  add  i  c.c.  of 
i  :  i  hydrochloric  acid  after  acidulation  with  sulphuric  acid. 

Place  in  the  beaker  a  square  inch  of  1.7  mm.  (^  inch  thick) 
aluminum  foil  with  its  corners  bent  at  right  angles.  Heat  the 
solution  so  as  to  maintain  rapid  action  between  the  foil  and  the 
acid.  In  a  half  hour  the  reduction  is  usually  complete. 

Titrate  with  potassium  permanganate  standard  until  3  drops 
of  the  latter  render  the  solution  a  distinct  pink,  in  the  cold, 
for  i  minute.  Remove  the  foil  before  beginning  the  titration, 
rinsing  it  with  cold  water.  Heat  a  similar  piece  of  foil  for  a 
half  hour  in  a  solution  containing  5  grams  of  sodium  carbonate 
acidulated  with  120  c.c.  i  :  3  sulphuric  acid.  Add  also  i  c.c. 
of  i  :  i  hydrochloric  acid  after  acidulating  with  sulphuric  acid. 
Titrate  the  blank  exactly  as  given  for  the  test.  Deduct  the 
c.c.  of  permanganate  used  by  the  blank  from  the  amount  re- 
quired to  oxidize  the  test,  and  multiply  the  remainder  by  0.001925 
to  obtain  the  weight  of  molybdenum  present  in  the  sample.  The 
permanganate  standard  is  prepared  by  dissolving  1.86  grams 
of  the  salt  in  water  and  diluting  the  solution  to  i  liter.  Its 
value  in  metallic  iron  multiplied  by  0.88163  equals  its  value  in 
Mo03.  This  method  possesses  no  advantage  over  the  ignition 
of  the  sulphide  to  oxide  and  weighing  as  such. 


METHOD  FOR  TUNGSTEN  AND  MOLYBDENUM  STEELS     133 

WEIGHING  or  THE  MOLYBDENUM  AS  LEAD  MOLYBDATE. 

After  weighing  as  oxide,  fuse  the  latter  with  5  grams  of  sodium 
carbonate.  Dissolve  the  melt  in  water.  Filter  it,  washing 
thoroughly  with  sodium  carbonate  water.  To  the  filtrate  and 
washings  add  2  or  3  drops  of  methyl  orange.  Now  titrate  the 
solution  until  it  turns  pink  with  i  :  i  HC1.  Add  i  c.c.  in 
excess.  Heat  the  solution  to  almost  boiling.  Add  30  c.c.  of  a 
filtered  saturated  solution  of  lead  acetate  in  this  manner:  First 
add  20  c.c.  and  permit  the  precipitate  to  settle  somewhat;  then 
pour  in  the  remaining  10  c.c.,  noting  if  there  seems  to  be  a  further 
formation  of  the  white  precipitate.  If  more  forms,  add  an  addi- 
tional 10  c.c.,  or  40  c.c.  in  all.  Now  add  50  c.c.  of  a  solution 
of  ammonium  acetate.*  Stir  the  mixture  thoroughly  and  allow 
the  lead  molybdate  to  settle  for  two  hours.  It  is  filtered,  washed 
with  hot  water,  and  ignited  at  a  low  red  heat  until  white.  It  is 
weighed  and  the  weight  multiplied  by  0.2616  to  reduce  the 
weight  to  metallic  molybdenum.  Test  the  filtrate  and  washings 
with  10  c.c.  of  the  lead  acetate  solution,  and  note  if  a  further 
precipitation  occurs  in  the  course  of  an  hour  or  two.  This  is  a 
satisfactory  method,  as  a  check.  The  ammonium  acetate 
solution  is  prepared  by  dissolving  500  grams  of  the  crystals  in 
1000  c.c.  of  water. 

*  Brearley  and  Ibbotson  suggested  the  use  of  ammonium  acetate  at  this  stage. 


CHAPTER  V. 

PART  V. 

DETERMINATION  OF  TIN  AND  BISMUTH  IN  PLAIN 
AND  ALLOY  STEELS. 

DISSOLVE  2  grams  of  drillings  by  heating  the  same  in  a  No.  5 
porcelain  dish  on  the  water  bath.  After  action  with  HC1  is 
over  begin  to  further  attack  the  steel,  if  it  contains  large  quan- 
tities of  chromium  and  tungsten,  by  additions  of  potassium 
chlorate,  .0.500  gram  at  a  time  at  intervals  of  30  minutes  until 
the  insoluble  residue  is  bright  yellow  if  tungsten  be  present. 
Heat  until  all  smell  of  chlorine  is  gone.  The  sample  is  usually 
well  decomposed  when  the  amount  of  chlorate  added  equals 
about  2  grams.  Now  add  50  c.c.  of  water;  heat  for  a  half 
hour;  filter  out  the  insoluble  residue  and  wash  the  same  free 
of  iron  test  with  dilute  HC1. 

The  filtrate  and  washings  are  made  nearly  neutral  with  am- 
monia and  20  c.c.  of  a  cinchonine  solution  are  added,  if  the  steel 
contains  tungsten,  to  remove  the  last  traces  of  the  latter.  The 
solution  is  allowed  to  stand  over  night  to  make  sure  that  all 
traces  of  tungsten  are  separated.  The  tungsten  is  then  filtered 
out,  and  the  filter  is  washed  with  cinchonine  water  as  in  the 
determination  of  tungsten.  Any  traces  of  tungsten  remaining 
behind  are  very  likely  to  contaminate  the  tin  sulphide,  obtained 
later.  (This  cinchonine  solution  is  made  by  dissolving  50 
grams  of  the  latter  alkaloid  in  200  c.c.  cone.  HC1  and  800  c.c.  of 
water.) 

The  filtrate  and  washings  from  the  cinchonine  precipitation 
are  diluted  to  400  c.c.  and  hydrogen  sulphide  is  passed  until  the 
mixture  of  sulphur  and  sulphides  settle  well  in  the  hot  solution. 
The  sulphides  are  filtered  off  and  washed  with  hydrogen  sul- 
phide water  until  free  of  ferrous  iron  test  with  ferricyanide  of 

134 


DETERMINATION  OF  TIN  AND   BISMUTH  IN  STEELS      135 

potassium.  This  requires  50  washings.  Two  drops  of  the  i  :  i 
HC1  are  put  in  500  c.c.  of  this  wash. 

Burn  off  the  mixture  of  sulphides  at  a  very  low  red  heat  in 
a  weighed  porcelain  crucible.  The  residue  in  the  crucible  may 
contain  small  amounts  of  oxides  of  copper,  molybdenum,  bis- 
muth, iron  and  silicon  besides  the  oxides  of  tin.  The  oxides  are 
heated  at  a  red  heat  for  a  half  hour  after  the  paper  is  all  burned 
away.  The  total  weight  of  the  oxides  is  obtained  and  then  the 
oxides  are  extracted  with  20  c.c.  of  cone,  ammonia  to  remove 
the  molybdenum.  The  residue  insoluble  in  ammonia  is  filtered 
off;  washed  with  ammonia  water;  burned  off  as  before;  and  is 
then  heated  with  i  :  i  HC1  to  remove  the  small  amount  of  iron, 
copper  and  bismuth  that  may  be  present.  Again  the  residue  in- 
soluble in  the  HC1  is  filtered  off;  washed;  and  weighed.  This 
weight  represents  the  tin  oxide  together  with  a  little  silica.  To 
remove  the  silica  the  residue,  after  being  weighed  free  of  the 
iron,  bismuth  and  copper,  is  transferred  to  a  platinum  crucible, 
moistened  with  5  drops  of  the  cone.  H^SC^  and  evaporated  to 
dry  ness  with  5  c.c.  of  HF1  to  remove  the  silica.  The  crucible  is 
then  heated  to  redness  again,  cooled  and  weighed.  The  weight 
so  obtained  is  calculated  to  metallic  tin  by  multiplying  by  the 
factor  0.7887.  A  first  class  steel  will  not  show  by  this  method 
much  over  0.050  per  cent  Sn.  The  author  has  repeatedly  had 
the  method  tested  by  adding  known  amounts  of  tin  to  alloy 
steels;  and  has  recovered  the  amounts  added  within  a  fraction 
of  a  milligram.  It  must  be  remembered,  in  this  connection,  that 
chloride  of  tin  is  volatile;  for  this  reason  the  author  never  heats 
the  samples  above  the  water  bath  temperature  during  the  de- 
composition with  hydrochloric  acid  and  chlorate. 

In  case  it  is  desired  to  determine  both  tin  and  bismuth,  it  is 
better  to  separate  these  two  elements,  as  given  under  the  deter- 
mination of  Bi  and  Sn  in  tungsten  powder,  when  much  tin  and 
bismuth  are  present,  page  88,  by  the  use  of  yellow  ammonium 
sulphide  and  flowers  of  sulphur. 


CHAPTER  VI. 
PART  I. 

ANALYSIS  OF  FERRO-CHROME,  CHROME  ORE  AND  CAR- 
BONLESS CHROME. 

FERRO-CHROME  and  carbonless  chrome  usually  dissolve 
completely  in  i  :  3  sulphuric  acid.  The  ferro  should  be  ground 
as  fine  as  possible.  Carbonless  chrome  dissolves  readily  with- 
out grinding  to  any  especial  degree. 

When  a  residue  of  a  gritty  or  metallic  nature  remains  after 
digestion  with  the  dilute  acid,  it  is  filtered  out,  washed  twenty 
times  with  i  :  10  sulphuric  acid,  roasted,  fused  with  twenty 
times  its  weight  of  sodium  carbonate  plus  a  fifth  of  its  weight  of 
potassium  nitrate.  The  fusion  is  dissolved  in  water  in  a  platinum 
dish,  or  porcelain  one,  and  then  poured  into  the  main  solution. 

*  Dissolve  from  0.3  to  0.4  gram  of  sample  in  30  c.c.  i  :  3  sul- 
phuric acid  as  described,  fusing  the  residue  if  there  be  any.  Add 
60  c.c.  1.20  nitric  acid,  and  treat  exactly  as  stated  for  determina- 
tion of  vanadium  in  ferro-vanadium  until  the  filtering  through 
asbestos  to  remove  the  excess  of  manganese  oxide  has  been  ac- 
complished. To  the  cold  filtrate  add  from  i  to  2  c.c.  of  the  ferri- 
cyanide  indicator.  Add  also  50  c.c.  of  1:3  sulphuric  acid. 
Titrate  at  once  with  a  standard  solution  of  ferrous  ammonium 
sulphate  of  double  the  strength  of  that  used  for  vanadium  work. 
When  3  drops  of  this  standard  produce  a  darkening  of  the 
green  to  a  blue,  after  the  entire  disappearance  of  all  red  or 
yellow  tints,  the  end  point  is  reached. 

STANDARDIZATION  AND  CALCULATIONS. 

Dissolve  39.163  grams  of  ferrous  ammonium  sulphate  in  water; 
add  50  c.c.  of  i  :  3  sulphuric  acid;  and  dilute  to  i  liter  for 
standard.  To  standardize  the  ferrous  ammonium  sulphate 

*  Use  from  0.2  to  0.25  gram  if  Cr  in  the  ferro  is  over  50  per  cent  Cr. 

136 


FERRO-CHROME,  CHROME  ORE  AND  CARBONLESS  CHROME     137 

weigh  into  a  5  ounce  beaker  0.500  gram  of  recrystallized  c.p. 
potassium  dichromate.  Dissolve  these  crystals  in  a  small 
quantity  of  water.  Add  to  the  water  solution  sulphurous  acid 
until  the  chromate  is  entirely  reduced  to  a  dark  green  and  smells 
distinctly  of  SOz.  Then  transfer  this  green  solution  to  a  600  c.c. 
beaker  containing  about  as  much  steel,  free  from  chromium,  as 
there  is  supposed  to  be  iron  in  the  ferro-chromium.  For  exam- 
ple, if  the  ferro  is  supposed  to  contain  60  per  cent  chromium, 
use  o.i 60  gram  of  steel.  The  steel  is  dissolved  in  30  c.c. 
i  :  3  sulphuric  acid  before  the  reduced  chromium  solution  is 
added  to  it.  Put  this  standardizing  mixture  through  all  of 
the  analytical  operations  given  for  the  actual  analysis  of  the 
ferro-chromium,  including  the  addition  of  the  nitric  acid. 


CALCULATIONS. 

The  ferrous  ammonium  sulphate  used  by  the  0.500  gram  KgCr-jOr  is,  for  example, 
102.6  c.c.  The  percentage  of  chromium  in  the  dichromate  is  35.35.  Therefore 
0.500  X  35.35  -5-  102.6  =  0.001724,  or  i  c.c.  of  dichromate  equals  0.001724  gram 
of  chromium. 

A  check  standardization  using  0.600  gram  of  K2Cr2O7  gave  i  c.c.  equals  0.001713. 
The  average  value  is  0.001718.  Suppose  0.300  gram  of  a  ferro-chromium  required 
99.9  c.c.  of  the  sulphate  standard:  99.9  X  0.001718  -+•  0.3  =  0.5721,  or  57.21  per 
cent  chromium. 


CARBON. 

The  total  carbon  can  be  obtained  quickly  by  the  means  of  some 
oxidizing  flux  in  a  stream  of  oxygen.  Direct  combustions  with 
oxygen  alone  are  very  incomplete,  at  least  with  temperatures 
of  950°  C.  and  under.  Decarbonize  i  gram  of  6o-mesh  sample 
with  4  grams  of  red  lead,  either  in  the  gas  or  electrically  heated 
furnaces.  (See  pages  203  to  245.) 

ALUMINUM.* 
Proceed  as  in  ferro-vanadium,  page  18. 

*  Read  near  the  bottom  of  page  139. 


138  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

PHOSPHORUS  AND  SULPHUR. 

Fuse  2  grams,  twice,  with  sodium  carbonate  and  niter.  Fuse 
each  time  with  20  grams  of  carbonate  and  5  of  niter.  Add  5  c.c. 
of  the  aluminate.  Precipitate  the  combined  nitrates  from  the 
water  solutions  of  the  fusions  with  i  :  i  HC1  and  proceed  as  in 
ferro- vanadium,  getting  the  sulphur  by  completely  acidulating 
the  filtrate  from  the  aluminum  hydroxide,  evaporating  once  to 
dryness,  filtering  and  finishing  by  barium  chloride  in  acid  solu- 
tion. Obtain  blanks  on  fluxes  and  reagents  and  deduct  the  same 
from  the  barium  sulphate  found.  A  third  fusion  is  often  neces- 
sary to  remove  all  chromium,  phosphorus,  aluminum  and  sul- 
phur from  the  ferro-chrome. 

Second  Method  for  Phosphorus  and  Aluminum. 

Fuse  2  grams  of  finely  ground  sample  twice  for  five  minutes 
with  sodium  peroxide  in  a  nickel  crucible.  Dissolve  in  water, 
in  a  dish,  as  described  under  chrome  ore.  Filter  after  each 
fusion,  washing  with  sodium  peroxide  water.  For  phosphorus 
the  combined  filtrates  are  treated  with  5  c.c.  of  the  sodium 
aluminate  solution,  and  phosphorus  and  sulphur  determinations 
are  then  proceeded  with  as  in  the  sodium  carbonate  and  niter 
fusion  method:  The  aluminum  hydroxide  is  precipitated  by 
adding  i  :  i  hydrochloric  acid  until  the  former  settles  out  well, 
still  keeping  the  solution  slightly  alkaline  to  prevent  interference 
of  the  chromium.  The  water  solutions  of  the  fusion  should  be 
boiled  10  seconds  in  porcelain  or  platinum  vessels  to  remove  the 
hydrogen  peroxide  before  adding  hydrochloric  acid  to  precipi- 
tate the  aluminum  as  hydroxide,  hydrogen  peroxide  being  a 
reducing  agent  in  acid  solution. 

For  Aluminum. 

(i)  First  add  to  the  filtered,  hot  water  solution  of  the  peroxide 
fusions  i  :  i  hydrochloric  acid,  and  note  if  any  cloudiness  or 
white  precipitate  forms  before  acidity  is  reached.  If  a  precipi- 
tate appears,  it  is  filtered  out,  washed  and  examined  for  alu- 


FERRO-CHROME,  CHROME  ORE  AND  CARBONLESS  CHROME     139 

minum,  silicon  and  phosphorus  as  given  under  ferro-vanadium, 
page  19. 

(2)  To  the  filtrate  from  the  aluminum  add  5  c.c.  of  sodium 
aluminate  and  5  grams  of  sodium  carbonate.     Precipitate  the 
remainder  of  the  phosphorus  as  aluminum  phosphate,  and  pro- 
ceed as  already  described  for  phosphorus  and  sulphur.     Add 
the  phosphorus  obtained  from  the  aluminum,  if  any  is  found  in 
the  ferro,  to  that  obtained  from  the  added  aluminate,  to  get  the 
total  phosphorus. 

(3)  To  avoid  (2),  100  mgs.  of  metallic  aluminum  can  be  added 
to  (i)  to  insure  the  presence  of  sufficient  aluminum  to  carry 
out  all  of  the  phosphorus.     The  metal  is  added  as  chloride  by 
dissolving  it  in  10  c.c.  of  i  :  i  HC1.     Deduct  this  100  mgs.  from 
the  total  aluminum  found  to  get  the  aluminum  in  the  test. 

Third  Method  for  Phosphorus,  Sulphur  and  Aluminum. 

(A)  Fuse  i  gram  of  the  finely  ground  sample  with  10  grams 
of  sodium  carbonate  and  2  grams  of  niter.     Dissolve  the  fusion 
in  water.     Filter,  wash  with  sodium  carbonate  water.     Roast 
the  residue  at  a  low  red  heat  until  filter  paper  is  gone.     Dis- 
solve the  oxides  in  hydrochloric  acid,  and  transfer  the  solution 
to  a  1000  c.c.  boiling  flask.     Make  a  peroxidation,  adding  100 
mgs.  of  metallic  aluminum  exactly  as  given  under  the  second 
method  for  phosphorus  in  ferro-vanadium,  page  24. 

(B)  The  filtrate  and  washings  from  the  water  solution  of 
the  sodium  carbonate  and  niter  fusion  are  examined  for  phos- 
phorus, sulphur  and  aluminum  exactly  as  given  under  the  first 
method  for  these  elements. 

For  phosphorus  the  aluminum  hydroxide  precipitates  ob- 
tained from  the  peroxidation  (A)  and  from  the  filtrate  from 
the  sodium  carbonate  and  niter  fusions  (B)  are  combined  by 
putting  the  hydrochloric  solutions  of  the  aluminum  hydroxide 
precipitates  together  before  converting  to  nitrates.  Finish  as 
in  the  first  method. 

The  object  of  this  third  method  is  to  avoid  all  but  one  of  the 
fusions  required  in  the  first  method.  Deduct  blanks  made  on 


140  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

all  acids,  sodium  peroxide  and  fluxes  used.  (Either  by  sodium 
peroxide  fusions  or  by  sodium  carbonate  and  niter  fusions  con- 
siderable yellow  chromate  color  is  obtained  from  the  water 
solution  of  third  fusions  of  ferro-chromium.) 

SILICON. 

Obtain  the  silicon  as  in  high  silicon  f erro-vanadium ;  i.e.,  fuse 
if  necessary,  acidulate  with  hydrochloric  acid,  and  evaporate 
twice  to  dryness. 

MANGANESE. 

Remove  the  chromium  by  zinc  oxide,  and  proceed  as  in  chrome 
steel  soluble  in  sulphuric  acid. 

If  fusions  are  required,  separate  the  manganese  by  prolonged 
heating  of  the  water  solutions  of  the  double  fusions  with  alcohol 
as  in  high  manganese  f  erro-vanadium.  (Page  16.) 

IRON. 

The  residue  from  the  water  solution  of  sodium  carbonate 
and  niter  fusions  is  treated  for  iron  as  outlined  for  iron  in  ferro- 
vanadium.  Or  the  precipitates  remaining  on  niters  after  sepa- 
rating chromium,  aluminum  and  phosphorus  by  the  peroxide 
method  can  be  roasted,  dissolved  in  cone,  hydrochloric  acid, 
evaporated  to  fumes  with  sulphuric  acid,  reduced  with  zinc 
and  titrated  with  permanganate  solution  for  iron  as  in  f  erro- 
vanadium. 

CHROMIUM  IN  CHROME  ORE. 

Fuse  0.6  gram  with  8  grams  of  sodium  peroxide  in  a  45  c.c. 
porcelain  crucible.  Keep  the  fusion  molten  for  five  minutes. 
Three  or  four  melts  can  be  made  of  chrome  ore  in  a  porcelain 
crucible  before  the  peroxide  cuts  through. 

Place  the  crucible  in  a  375  c.c.  casserole.  Cover  with  a  watch 
glass.  Stand  the  crucible  in  the  bottom  of  the  casserole.  Allow 
water  to  flow  slowly  down  the  under  side  of  the  watch  glass  and 
drop  into  the  open  crucible.  The  melt  promptly  boils  up  and 
dissolves  in  a  few  moments.  Remove  the  crucible.  Boil  the 


FERRO-CHROME,  CHROME  ORE  AND  CARBONLESS  CHROME    141 

water  solution,  without  filtering,  for  one-half  hour  to  remove 
all  hydrogen  peroxide.  The  excess  of  peroxide  would  reduce 
some  of  the  chromic  acid,  if  allowed  to  remain,  just  as  soon  as 
the  fusion  is  acidulated  with  the  sulphuric  acid.  Add  50  c.c. 
excess  of  i  :  3  sulphuric  acid. 

Add  3  c.c.  of  the  ferricyanide  indicator  to  the  cold  sulphuric 
acid  solution  and  titrate  it  as  in  ferro-chrome  using  the  same 
standard.  Standardize  by  fusing  0.340  gram  of  potassium 
dichromate  in  8  grams  of  peroxide  in  a  porcelain  crucible,  and 
complete  the  operation  as  in  actual  analysis.  Multiply  the 
number  of  milligrams  of  metallic  chromium  found  by  152  and 
divide  by  104  to  obtain  the  milligrams  of  chromium  oxide  in 
the  ore,  or 

Cr  X  ^  =  Cr203. 

i3 

As  the  samples  of  ferro-chromium  and  chrome  ore  are  likely 
to  vary  somewhat,  especially  in  the  case  of  ferro-chromium, 
several  determinations  should  be  made  of  the  same  sample  and 
the  results  averaged. 

Porcelain  crucibles  are  not  suitable  for  fusion  of  metals  with 
sodium  peroxide,  as  great  heat  is  generated,  causing  the  crucible 
to  crack.  This  is  not  the  case  in  chrome  ore. 

INSOLUBLE  FERRO-CHROMIUM. 

Ferro-chrome  that  is  not  attacked  by  acids  can  be  conven- 
iently assayed  for  chromium  as  given  for  chrome  ore,  but  as 
the  procelain  crucible  usually  cracks  during  the  cooling  a  new 
crucible  is  needed  for  each  fusion.* 

Weigh  0.500  f  gram  of  the  finely  ground  ferro  and  fuse  it 
with  8  grams  of  sodium  peroxide. 

*  Iron  crucibles  are  preferable  for  this  work.  Use  a  65  c.c.  crucible.  Keeping 
the  lid  on,  grasp  the  body  of  the  crucible  with  the  forceps;  hold  it  in  the  flame  of 
a  Bunsen  burner  until  molten.  Then  give  the  crucible  a  slight  rotary  motion 
for  a  period  of  3  or  4  minutes,  or  until  the  entire  mass  is  in  a  state  of  homogeneous 
fusion. 

t  From  0.2  to  6.25  gram  if  Cr  in  the  ferro  exceeds  50  per  cent  Cr. 


142  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


THE  DETERMINATION  OF  CHROMIUM  IN  FERRO-CHROMIUM 
BY  FUSION  IN  AN  IRON  CRUCIBLE. 

Fuse  0.200  gram  of  the  ferro  if  the  chromium  is  about  65  to 
70  per  cent  in  chromium  content,  or  a  proportionately  larger 
weight  if  the  chromium  content  is  lower,  in  a  70  c.c.  iron  cru- 
cible with  8  grams  of  sodium  peroxide.  In  making  the  fusion 
the  crucible  is  held  in  a  pair  of  tongs  and  given  a  moderate 
swirling  motion  in  the  flame  of  an  ordinary  Bunsen  blast  burner. 
In  two  minutes  the  melt  should  be  liquid  and  after  two  more 
minutes  the  fusion  should  be  perfect.  During  the  fusing  it 
is  wise  to  place  the  burner  in  an  enameled  ware  pan  as,  in  case 
the  flux  cuts  through  the  crucible,  the  drops  of  the  red  hot  flux 
will  be  caught  in  the  pan,  instead  of  being  spread  far  and  wide. 
After  cooling  the  crucible  is  placed  in  a  600  c.c.  casserole;  a  lid 
is  placed  on  the  latter  and  the  fusion  is  dissolved  in  150  c.c.  of 
water  which  is  allowed  to  flow  very  slowly  down  under  the 
watch  glass  into  the  open  crucible.  The  water  solution  of  the 
fusion  is  boiled  for  a  half  hour  to  remove  all  hydrogen  peroxide; 
the  crucible  is  removed  from  the  casserole;  150  c.c.  of  i  :  3  sul- 
phuric acid  are  added;  and  the  solution  is  heated  for  10  minutes. 
The  iron  scales  are  filtered  out  on  an  asbestos  plug  (see  page  8) 
and  the  plug  is  washed  with  water  thoroughly;  the  filtrate  and 
washings  are  diluted  to  400  c.c.  with  distilled  water;  3  c.c.  of 
indicator  are  added  (5  grams  of  potassium  ferricyanide  dis- 
solved in  1 20  c.c.  of  water)  and  the  solution  is  titrated  to  the 
first  distinct  blue  with  the  same  standard  as  given  on  page  141. 

Chrome  Ore.  Chrome  can  also  be  analyzed  as  above  for 
chromium,  taking  0.500  gram  for  the  analysis;  but  for  the  most 
accurate  work  the  author  prefers  the  method  given  on  page  140, 
as  the  fusion  in  porcelain  dissolves  in  the  sulphuric  in  the  most 
satisfying  way,  being  as  clear  as  a  filtered  solution  except  for  a 
few  scattering  pure  white  flakes  of  floating  silicic  acid.  The 
fusion  in  porcelain  is  also  desirable  for  iron  determination  as 
the  sulphuric  acid  solution  can  be  reduced  at  once  without 


FERRO-CHROME,  CHROME  ORE  AND  CARBONLESS  CHROME     143 

separating  the  chromium  and  titrated  for  iron  with  the  standard 
permanganate  solution  (see  page  48). 

Standardization.  For  either  of  the  above  methods  fuse 
0.400  or  0.450  gram  of  recrystallized  potassium  dichromate  in 
8  grams  of  the  sodium  peroxide  and  put  the  same  through  all 
of  the  above  operations  and  titrate  the  resulting  solutions  with 
the  permanganate  solution  to  be  standardized,  calculating  the 
chromium  value  of  the  standard  in  the  same  manner  as  given 
on  page  48. 

Aluminum.  To  avoid  all  fusions  in  platinum  for  the  deter- 
mination of  this  element,  ferro-chromium  can  be  decomposed  in 
the  iron  crucible  as  above,  getting  the  sulphuric  acid  solution 
of  the  fusion  which  is  then  peroxidized  as  described  on  page  23, 
beginning  at  the  point  where  one  is  directed  to  dilute  to  about 
300  c.c.  Make  at  least  three  peroxidations  if  the  Al  is  10  per 
cent,  or  over,  using  hydrochloric  acid  to  redissohe  the  iron. 


CHAPTER  VI. 

PART  II. 
THE  ANALYSIS  OF  CHROME  CEMENT. 

Ignition  Loss.  Heat  i  gram  of  sample  for  a  half  hour  in  a 
weighed  platinum  crucible  at  a  bright  heat  and  weigh  the  cru- 
cible and  its  contents  again  and  note  the  loss  of  weight.  Return 
the  crucible  to  the  flame  and  heat  at  10  minute  intervals  until 
the  loss  for  10  minutes  heating  no  longer  exceeds  0.0002  gram. 
The  total  loss  of  weight  is  calculated  to  percentage  as  the  igni- 
tion loss. 

Silica,  Iron  and  Aluminum  Oxides.  Fuse  0.5  gram  of  sample 
with  15  grams  of  potassium  acid  sulphate  (KHSO4)  in  large 
platinum  crucible,  in  the  manner  described  on  page  51,  until 
a  clear  solution  is  obtained.  Cool;  dissolve  in  water  and 
hydrochloric  acid.  Boil;  filter  off  the  silica;  wash  it;  finish 
it  as  usual  getting  the  loss  of  weight  with  HF1  and  a  few 
drops  of  cone.  H2SO4.  The  residue  remaining  in  the  crucible 
after  this  evaporation  and  ignition  is  fused  with  4  grams  of 
KHSO4.  Dissolve  it  as  in  the  main  fusion,  adding  the  solution 
to  the  main  filtrate  from  the  silica.  This  filtrate  contains  all 
of  the  iron  and  aluminum.  The  aluminum  is  separated  from 
the  iron  by  peroxidation  with  sodium  peroxide  until  a  filtrate 
is  obtained  that  does  not  show  any  more  precipitate  with  the 
HC1  than  a  blank  determination.  (See  page  23.)  The  iron  on 
the  filter  from  the  last  filtration  together  with  any  that  may  be 
adhering  to  the  walls  of  the  peroxidation  flask  is  dissolved  in 
HC1  and  finished  by  reduction  with  stannous  chloride  as  in  iron 
ore.  The  iron  found  is  calculated  to  FeO.  The  aluminum  is 
purified  from  occluded  salts  by  redissolving  it  in  HC1  and  re- 
precipitating  it  with  a  slight  excess  of  ammonia.  Before  filter- 
ing off  the  aluminum  it  should  be  boiled  for  some  minutes. 

144 


THE  ANALYSIS  OF   CHROME  CEMENT 


145 


It  is  washed  with  ammonium  nitrate  wash,  ignited,  blasted, 
cooled  and  weighed  as  A12O3  plus  a  little  silica  which  is  removed 
by  evaporation  with  some  HF1  plus  10  drops  of  cone.  HaSO*. 
Deduct  blanks. 

Chromic  Oxide.  Fuse  0.3  or  0.4  gram  of  the  sample  in  8 
grams  of  sodium  peroxide  in  an  iron  crucible  and  finish  as  in 
chrome  ore.  (See  page  140.) 


RESULTS. 


Per  cent. 

Per  cent. 

Ignition  loss 

2    34 

vSilica 

3    21 

Iron  monoxide  (FeO).  . 
Alumina 

30.00 
21    2O 

Chromic  oxide  (Cr2Os).. 

40.80 

Note.      Sodium  carbonate  fusions  are  not  successful  as  a  method  of  decomposing 
the  above  cement. 


CHAPTER  VII. 
ALUMINUM  IN  STEEL. 

WEIGH  3  grams  of  chromium  and  tungsten  steel  or  6  grams 
of  plain  carbon  steel  into  a  half  liter  flask  filled  with  carbon 
dioxide.  Pour  into  the  flask  10  c.c.  i  :  i  hydrochloric  acid  for 
every  gram  of  steel.  Warm  until  action  ceases  with  C02  passing 
into  the  flask.  Cool,  and  add  a  saturated  solution  of  sodium 
carbonate  (use  a  measured  amount)  until  the  iron  precipitate 
dissolves  rather  slowly.  Now  add  a  slight  excess  of  barium 
carbonate  free  from  alumina.  Add  the  carbonate  in  a  thick 
paste.  Fill  the  flask  to  the  neck  with  water.  Mix  the  con- 
tents thoroughly  by  repeatedly  inverting  the  stoppered  flask. 
Permit  C02  to  escape,  occasionally,  during  the  mixing.  Allow 
the  contents  of  the  flask  to  settle  twelve  hours.  Mix  with  pulp; 
filter  and  wash  with  water  containing  5  gms.  of  NaCl  per  500  c.c. 
40  times  to  remove  the  greater  portion  of  the  ferrous  iron. 

Dissolve  the  residue  on  the  filter,  consisting  of  a  mixture  of 
tungsten,  iron,  aluminum  and  chromium  compounds,  with  hot 
i  :  i  hydrochloric  acid.  Wash  the  filter  free  of  iron  test.  Ash 
this  filter,  after  washing  it  free  of  acid,  in  a  porcelain  crucible. 
Transfer  the  ash  to  a  platinum  crucible  and  fuse  it  with  20 
times  its  weight  of  Na2CO3.  Dissolve  the  fusion  in  HC1  and 
add  it  to  the  main  solution  of  the  precipitate  obtained  as  above 
with  the  barium  carbonate.  Evaporate  the  filtrate  and  wash- 
ings from  the  solution  of  the  residue  to  20  c.c.  Cover  the  dish 
with  a  watch  glass  and  add  an  excess  of  potassium  chlorate. 
Heat  with  cover  on  until  all  spraying  is  over.  Remove  the 
cover  and  evaporate  to  dryness.  Add  20  c.c.  cone,  hydrochloric 
acid.  Cover  and  boil  gently  until  all  is  in  solution  except  a 
yellow  residue  of  tungstic  acid,  which  will  appear  if  the  steel 
contains  tungsten.  Add  50  c.c.  of  water.  Boil  twenty  minutes. 
Filter.  Wash  with  i  :  20  hydrochloric  acid  until  the  filter  no 

146 


ALUMINUM   IN   STEEL  147 

longer  gives  an  iron  test.  Evaporate  again  to  dryness.  Dis- 
solve, filter  and  wash  as  before.  Precipitate  the  filtrate  and 
washings  with  a  slight  excess  of  ammonia  in  a  casserole.  Boil  a 
few  minutes.  Add  paper  pulp;  use  ashless  pulp.  Filter.  Wash 
with  ammonium  nitrate  water  until  free  from  chloride  test.  Use 
the  same  number  of  filters  on  all  tests  and  on  the  blank  test. 
The  latter  is  made  at  the  same  time  as  the  regular  analysis. 
Roast  off  the  paper  in  a  large  platinum  crucible,  and  fuse  the 
ash  with  10  grams  of  sodium  carbonate  and  2  grams  of  niter, 
keeping  it  molten  for  a  half  hour.  Leach  out  with  water,  filter, 
wash,  add  i  :  i  hydrochloric  acid  to  this  fusion,  i  c.c.  at  a 
time,  until  the  aluminum  separates  out  in  a  white  flocculent 
precipitate  if  present  in  considerable  quantity,  or  until  the 
solution  looks  milky  if  the  percentage  is  small.  Be  sure  to  keep 
the  solution  at  all  times  distinctly  alkaline,  or  much  vanadium 
and  chromium,  if  any  be  present,  will  be  carried  out  with  the 
aluminum.  Proceed  further  as  in  ferro-vanadium.  (See  alu- 
minum in  ferro-vanadium,  page  18.) 

The  aluminum  gives  only  a  faint  cloudiness  to  the  solution 
if  present  in  small  quantity.  In  the  latter  case  wait  two  hours 
before  filtering. 

Fuse  the  iron  residue  a  second  time.  Dissolve  melt  in  water. 
Filter;  wash;  precipitate  with  acid.  If  much  precipitate  of 
aluminum  hydroxide,  etc.,  is  obtained  from  the  second  fusion, 
then  fuse  a  third  time  and  proceed  as  before.  Combine  all 
three  precipitates  of  aluminum  hydroxide  and  finish  as  given 
under  aluminum  in  ferro-vanadium,  page  18. 

Run  a  blank  including  all  chemicals  and  filter  paper  pulp; 
deduct  the  aluminum  so  obtained  from  the  final  weight  of  A12O3. 

Second  Method. 

Proceed  as  in  the  first  method  until  the  hydroxide  precipi- 
tates have  been  obtained  with  ammonia.  (After  the  chlorate 
treatment;  the  subsequent  evaporation  to  dryness;  and  re- 
moval of  any  tungsten  that  may  be  present.)  Roast  the  paper 
from  the  hydroxide  precipitates.  Dissolve  in  hydrochloric 


148  CHEMICAL  ANALYSIS   OF  SPECIAL   STEELS 

acid  and  transfer  this  solution  to  a  1000  c.c.  boiling  flask,  and 
then  finish  by  wet  sodium  peroxide  separation  as  given  under 
the  second  method  for  aluminum  in  ferro- vanadium,  page  23. 
Deduct  blanks.  Remove  phosphorus  and  silicon.  Multiply 
the  pure  A1203  by  53.033  and  divide  by  the  weight  taken  for 
analysis  to  obtain  per  cent  of  aluminum. 

The  separation  of  aluminum  from  iron  by  sodium  peroxide 
has  some  advantages.  If  the  operator  thinks  he  has  carried 
the  addition  of  the  HC1  too  far,  he  can  redissolve  the  hydroxide 
right  in  the  solution  by  adding  a  slight  excess  of  the  peroxide. 
Then  the  precipitation  can  be  repeated  with  more  caution  after 
the  usual  20  seconds  boiling  to  remove  the  excess  of  H2O2. 

While  it  is  not  essential,  it  is  easier  to  precipitate  aluminum 
hydroxide  free  from  vanadium  and  chromium  if  some  sodium 
carbonate  is  present.  The  carbon  dioxide  causes  the  aluminum 
hydroxide  to  precipitate  while  the  solution  in  which  the  precipita- 
tion occurs  is  still  alkaline.  For  this  reason  10  grams  of  sodium 
carbonate  are  added  to  all  solutions  from  which  aluminum  is  to 
be  precipitated  by  HC1  unless  the  carbonate  is  already  present. 

Small  Amounts  of  Aluminum,  Uranium,  Vanadium 
and  Chromium. 

Less  than  0.05  per  cent  of  aluminum,  uranium  or  vanadium 
can  be  separated  from  the  bulk  of  the  iron  in  50  grams  of  the 
sample  by  the  method  given  on  page  146.  The  residue  on  the 
filter  after  the  barium  carbonate  precipitation  consists  of  all  of 
the  U,  Cr,  V  and  Al  in  the  sample  together  with  the  excess  of 
barium  carbonate  and  some  iron.  Wash  the  residue  with  sodium 
chloride  water  about  twenty  times,  (i)  This  residue  can  be 
analyzed  for  Al  as  given  on  page  146.  (2)  It  can  be  ashed, 
fused  with  a  little  peroxide,  the  fusion  dissolved  in  HC1,  con- 
verted to  nitrates  and  finished  for  Cr  and  V  as  in  steel.  (3)  For 
uranium  the  ashed  residue  can  be  analyzed  as  in  carnotite  ore 
as  given  on  page  289. 

In  this  way  minute  percentages  of  the  above  elements  can  be  de- 
termined with  extreme  accuracy.  Also  minute  amounts  of  tita- 
nium can  be  separated  from  the  bulk  of  the  iron  in  the  same  way. 


CHAPTER  VIII. 

PART  I. 
COPPER  IN  STEEL  AND  PIG  IRON. 

DISSOLVE  15  grams  of  drillings  in  300  c.c.  of  1.20  nitric  acid 
in  an  800  c.c.  beaker.  Heat  until  all  action  ceases.  Add  an 
excess  of  KMnO4  solution  of  the  same  strength  as  used  for  phos- 
phorus in  steels.  Boil  gently  for  30  minutes.  If  the  KMnO4 
disappears  during  the  boiling,  add  more  of  it.  Steels  require 
from  4  to  8  c.c.  and  pig  iron  from  25  to  30  c.c.  of  the  permanga- 
nate solution. 

In  pig  iron  add  5  c.c.  of  hydrofluoric  acid  before  boiling  with 
permanganate  of  potash.  Heat  10  minutes.  Then  boil  with 
the  KMn04  solution. 

After  boiling  the  pig  iron  or  steel  with  permanganate  solution, 
add  enough  wet  pulp  to  nearly  fill  a  50  c.c.  graduated  cylinder. 
Filter  through  double  12  cm.  filters  into  an  800  c.c.  beaker. 
Wash  the  pulp,  etc.,  free  from  iron  with  a  dilute  nitric  acid  wash 
consisting  of  5  c.c.  of  1.20  nitric  acid  diluted  with  200  c.c.  of 
water.  This  takes  about  40  washings.* 

To  pig  iron  or  steel  containing  from  o.oio  to  0.030  per  cent  of 
copper,  add  at  this  stage  20  c.c.  of  a  solution  of  potassium  ferri- 
cyanide,  made  by  dissolving  5  grams  of  the  crystals  in  120  c.c. 
of  distilled  water.  Stir  thoroughly  and  permit  the  solutions  to 
stand. 

If  the  copper  content  is  unusually  high,  add  2  c.c.  of  the 
ferricyanide  solution  for  every  milligram  of  copper  supposed 
to  be  present  in  the  steel.  If  nickel  is  present,  it  is  precipitated 
with  the  copper,  but  forms  more  slowly. 

As  there  is  a  tendency  to  form  blue  cyanide  of  iron  the  filtra- 

*  Read  near  the  top  of  page  152  concerning  the  addition  of  ammonia  to  pre- 
vent excessive  formation  of  iron  cyanide. 

149 


150  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

tions  should  be  proceeded  with  in  about  a  half  hour.  Add  as 
much  paper  pulp  as  in  the  first  nitrations,  filter  and  wash  five 
or  ten  times  with  water  containing  5  c.c.  of  ferricyanide  solution 
per  100  c.c.  of  distilled  water.  Use  a  15  cm.  filter. 

Roast  off  the  pulp  in  a  porcelain  crucible.  Dissolve  the  iron, 
nickel  and  copper  oxides  with  5  c.c.  of  cone,  hydrochloric  acid. 
Rinse  the  solution  into  a  200  c.c.  beaker.  Dilute  to  150  c.c. 
with  water  and  pass  H2S  for  a  half  hour  at  a  rapid  rate.  This 
removes  the  copper  from  nickel  and  any  iron  that  may  have  been 
precipitated  as  cyanide. 

Filter  on  a  small  filter;  wash  twenty  times  with  H2S  water. 
Burn  the  paper  in  a  45  c.c.  porcelain  crucible.  Dissolve  the 
oxide  in  20  c.c.  1.20  nitric  acid,  warming  until  all  black  residue 
is  dissolved  except  perhaps  an  occasional  flake  of  carbon  from 
the  filter  paper.  Rinse  the  solution  into  a  5  ounce  beaker, 
keeping  the  volume  as.  low  as  possible  for  copper  of  0.020  per 
cent  and  under,  in  order  that  the  blue  color  with  ammonia  may 
be  distinct.  Copper  as  low  as  0.015  Per  cent  gives  a  distinct 
blue  if  properly  manipulated.  Now  add  a  saturated  solution 
of  sodium  carbonate,  a  little  at  a  time,  until  a  precipitate  forms. 
Then  add  0.5  c.c.  of  cone,  ammonia.  Titration  follows  with  a 
standard  solution  of  potassium  cyanide,  made  by  dissolving 
2.244  grams  of  potassium  cyanide  and  5  grams  of  stick  potassium 
hydroxide  in  water  and  diluting  to  1000  c.c.  i  c.c.  of  this 
standard  should  equal  about  0.00064  to  0.00069  gram  of  metallic 
copper.  Standardize  the  solution  by  adding  10  and  15  mgs. 
of  metallic  copper  of  99.8  per  cent  Cu  to  15  grams  of  any 
steel  or  pig  iron.  Weigh  out  also  two  15  gram  portions  of 
this  same  steel  or  iron,  but  add  no  copper  to  them.  Put  all 
four  weights  through  the  entire  operation,  titrating  each  one 
to  the  disappearance  of  the  blue  as  given  under  " Titration." 

Titration.  Place  a  5  ounce  beaker  containing  distilled  water 
beside  the  one  containing  the  copper  to  be  tested.  Add  the 
cyanide  standard  to  the  test  until  it  is  as  free  from  even  a  slight 
blue  tint  as  the  beaker  of  distilled  water. 

This  method  has  been  tested  with  known  amounts  of  copper 


COPPER  IN  STEEL  AND   PIG  IRON  151 

added  to  steels,  and  with  steels  standardized  by  the  old  standard 
methods.  It  is  much  more  rapid,  and  results  check  very  sat- 
isfactorily. Filtrations  might  be  hastened  by  using  pulp  niters 
on  porcelain  plates  and  applying  slight  suction. 

CALCULATIONS. 

Pig  Iron  Sample. 

(1)  16.0  second  reading  of  burette. 

7.9  first  reading  of  burette. 
8.1  equals  c.c.  of  standard  used. 
No  copper  added. 

(2)  48.0 
15  mgs.  copper  added  16.2 

31.8  equals  c.c.  of  standard  used. 

(3)  10  mgs.  copper  added  23.6 

o.o 
23.6  equals  c.c.  of  standard  used. 

(4)  31.8  —  8.1  equals  c.c.  of  standard  used  by  15  mgs.  Cu. 

(5)  23.6  —  8.1  equals  c.c.  of  standard  used  by  10  mgs.  Cu. 

(6)  From  (4)  we  have  15  -5-  23.7  =  0.632,  or  i  c.c.  of  cyanide  equals  0.000632 
gram  Cu.     (0.998  X  15  -f-  23.7.) 

(7)  From  (5)  we  have  10  -5-  15.5  =  0.643,  or  J  c-c-  °f  cyanide  equals  0.000643 
grams  Cu.     (0.998  X  10  -5-  15.5.) 

(8)  From  (i)  we  have  8.1  X  0.00064  -r-  15  X  100  =  0.0345,  or  0.0345  per 
cent  copper  in  the  sample  of  pig  iron,  15  grams  having  been  taken  for  analysis. 

QUALITATIVE  VALUE. 

With  2  grams  of  sample  as  little  as  o.i  per  cent  of  copper 
gives  a  very  noticeable  yellowish  cloud  when  the  potassium 
ferricyanide  is  added  to  a  solution  of  steel  treated  as  described. 
Hence  the  method  affords  a  rapid  qualitative  test  for  the  pres- 
ence of  copper  in  sufficient  quantity  to  be  injurious  (0.05  per 
cent  and  over)  for  most  purposes  for  which  fine  tool  steel  is  used. 
The  operator  can  easily  decide  whether  the  precipitate  is  copper 
or  nickel.  If  it  is  copper,  the  precipitation  is  almost  instanta- 
neous. If  it  is  nickel,  the  reaction  is  noticeably  slower  and  the 
precipitate  is  of  a  brown  color,  closely  resembling  that  of  iron 
hydroxide.  A  yellowish  cloud,  forming,  at  once,  on  the  addition 
of  the  first  c.c.  of  the  precipitant,  is  characteristic  of  copper.  If 


152  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

this  be  followed  by  a  more  slowly  forming  brown  precipitate,* 
then  both  elements  are  present.  Many  makers  of  tool  steel 
insist  that  the  copper  content  of  best  tool  steel  be  under  0.02 
per  cent.  Several  steels  doing  fine  work,  however,  have  been 
analyzed  by  the  author  and  found  to  contain  copper  greatly 
in  excess  of  this  limit.  It  is  largely  a  question  of  what  sort  of 
a  tool  is  to  be  made  from  the  steel. 

The  tendency  to  form  blue  ferricyanides  of  iron  on  adding 
potassium  ferricyanide  to  ferric  solutions,  the  author  has  found, 
can  be  eliminated  sufficiently  to  prevent  serious  clogging  of  filters, 
by  keeping  the  iron  solution  somewhat  neutral,  after  first  boiling 
it  with  an  excess  of  permanganate  solution  and  filtering  out  the 
excess  of  manganese  oxide.  After  removing  the  latter  by  filtra- 
tion, add  i  :  i  ammonia  until  the  hydroxide  of  iron  dissolves 
rather  slowly.f  Then  add  the  ferricyanide  and  proceed  as 
already  described. 

As  the  copper  ferricyanide  precipitates  almost  instantly,  form- 
ing a  very  considerable  cloud  of  yellowish  precipitate  even  with 
0.03  per  cent  copper,  it  is  very  finely  divided,  and  has  a  tendency 
to  run  through  the  filter.  The  first  portion  that  is  filtered  should 
be  poured  back  on  the  paper  until  it  runs  through  clear.  Then 
proceed  with  the  filtration.  Stand  the  main  filtrate  aside 
when  washing  begins,  and,  should  the  latter  be  cloudy,  filter  with 
a  little  pulp  on  a  small  filter  and  add  it  to  the  main  precipitate.J 

When  precipitating  a  large  quantity  §  of  copper  by  this 
method  —  for  example,  sixty  or  one  hundred  milligrams  —  the 

*  Add  at  least  20  c.c.  of  the  ferricyanide  when  testing  for  nickel. 

f  Do  not  carry  the  neutralization  too  far  as  in  nearly  neutral  solutions  the 
nickel  and  copper  precipitate  very  slowly  with  the  ferricyanide. 

I  Pay  no  attention  to  any  clouding  of  the  filtrate  that  may  occur  after  the 
latter  has  stood  for  some  time. 

§  The  foregoing  method  is  especially  useful  for  very  small  per  cents  of  Cu  and 
Ni,  i.e.,  o.ioo  down  to  0.005  per  cent,  as  from  15  to  20  grams  of  sample  can  be  taken. 
For  higher  per  cents  it  is  easier  to  weigh  out  from  i  to  3  grams  of  plain  carbon 
steel;  dissolve  in  i  :  i  HC1  and  pass  H2S  at  once.  Then  finish  as  in  the  ferri- 
cyanide method  from  the  point  where  H2S  was  passed  through  the  solution  of 
the  copper  and  iron  oxides. 

The  ferricyanide  method  is  the  best  for  high  speed  steels.     See  page  156,  the 
bottom  paragraph.    Read  also  page  154  in  this  connection. 


COPPER   IN  STEEL   AND   PIG  IRON  153 

nearly  neutral  solution  should  be  largely  diluted,  making  the 
volume  from  about  800  c.c.  before  adding  the  precipitant.  (See 
Separation  of  Copper  and  Nickel  from  Vanadium  by  Ferri- 
cyanide  of  Potassium.)  It  is  better  to  precipitate  such  large 
amounts  of  copper  with  H2S. 

SMALL  AMOUNTS  OF  COPPER  AND  NICKEL  IN  STEEL'  AND 

IRON. 

When  analyzing  steel,  iron,  etc.,  for  copper,  do  not  carry  the 
neutralization,  given  in  the  top  paragraph  of  page  152,  too  far, 
as  in  nearly  neutral  solutions,  small  amounts  of  nickel  ferri- 
cyanide  precipitate  very  slowly,  and  the  precipitation  of  the 
copper  ferricyanide  is  also  delayed. 

The  method  described  for  copper  on  pages  149  to  152  is  designed 
for  small  amounts  of  copper,  that  is,  for  percentages  ranging 
from  o.ioo  to  o.ooi  and  for  equally  low  per  cents  of  nickel.  If 
nickel  in  such  small  per  cents  is  asked  for,  get  the  ferricyanide 
precipitates  of  the  nickel  and  copper  together  in  the  same  way  as 
directed  on  pages  154  to  156  using  15  grams  of  sample  and  the 
same  method  of  solution  as  given  for  copper  in  steel,  pages  149 
to  151,  separating  the  nickel  from  the  copper  and  determining  it 
as  given  on  pages  154  to  156. 

LARGE  AMOUNTS  OF  COPPER  IN  PLAIN  AND  ALLOY 
STEELS. 

If  the  percentage  of  copper  exceeds  o.ioo  per  cent,  then  dis- 
solve but  i  or  2  grams  of  the  sample,  and  proceed  as  described. 
If  the  sample  is  an  alloy  steel,  then  it  is  necessary  to  decompose 
the  same  in  the  manner  given  for  chromium  on  page  8,  whether 
the  amount  of  copper  be  large  or  small.  If  the  amount  is  small 
then  15  grams  should  be  taken  for  the  analysis  and  a  propor- 
tionate amount  of  sulphuric  acid  followed  by  an  equal  amount 
of  the  i. 20  nitric  acid,  that  is,  200  c.c.  of  the  i  :  3  sulphuric 
acid;  and  after  the  action  of  this  acid  is  over,  aided  by  heating 
for  a  half  hour,  then  200  c.c.  of  the  1.20  nitric  acid  are  added  and 
the  analysis  is  finished  as  for  copper  in  plain  carbon  steel. 


CHAPTER  VIII. 

PART  II. 

SEPARATION  OF  NICKEL  AND  COPPER  FROM  IRON  AND 
VANADIUM  BY  POTASSIUM  FERRICYANIDE. 

PROCEED  as  outlined  for  copper  in  steel,  except  smaller  weights 
of  sample  are  usually  required. 

For  nickel  and  copper  in  ferro-vanadium  dissolve  i  or  2 
grams  of  sample,  using  30  c.c.  of  1.20  nitric  acid  for  each  gram. 
If  the  ferro  is  high  in  silicon,  carbon  and  aluminum,  and  for  this 
reason  only  partly  soluble  in  nitric  acid,  add  a  few  c.c.  of  hydro- 
fluoric acid  to  the  solution  after  action  with  nitric  acid  is  over. 
Heat  until  all  metallic  or  gritty  particles  are  in  solution.  Or 
the  insoluble  part  can  be  broken  up  by  a  sodium  carbonate  and 
niter  fusion;  dissolved  in  hydrochloric  acid;  the  latter  removed 
by  evaporation  to  fumes  with  sulphuric  acid;  the  sulphate  dis- 
solved in  water  and  returned  to  the  main  solution.  Then  boil 
the  latter  with  an  excess  of  permanganate  solution;  filter  out 
the  manganese  oxide  as  described  under  Copper  in  Steel.  To  the 
filtrate  and  washings  i  :  i  ammonia  is  added  until  a  slight  pre- 
cipitate of  hydroxide  is  obtained  that  dissolves  slowly.  The 
copper  and  nickel -are  precipitated  with  potassium  ferricyanide 
as  in  Copper  in  Steel.  Large  amounts  of  nickel  —  i.e.,  from 
0.025  to  0.050  gram  —  precipitate  quickly,  but  smaller  quantities 
should  be  permitted  to  settle  for  one  hour  before  filtering.  It 
is  best  to  let  all  nickel  tests  stand  at  least  one  hour.  Add  as 
much  paper  pulp  from  ashless  filters  as  will  nearly  fill  a  15  cm. 
filter.  The  precipitate  and  pulp  are  filtered  out;  washed  a  few 
times;  dried;  ignited  in  a  large  porcelain  crucible;  the  ash 
transferred  to  a  6  ounce  beaker;  dissolved  in  30  c.c.  of  aqua 
regia.  Clean  the  crucibles  with  10  c.c.  of  the  latter  and  add 
the  cleanings  to  the  main  part.  (Nickel  oxide  dissolves  with 

154 


SEPARATION   OF  NICKEL  AND  COPPER   FROM   IRON,  ETC.      155 

some  difficulty,  requiring  considerable  heating.)  50  c.c.  i  :  3 
sulphuric  acid  are  added  to  the  solution;  evaporated  to  12  c.c.; 
diluted  to  300  c.c.;  the  copper  is  precipitated  with  H2S;  filtered 
out  and  washed  thoroughly  with  H2S  water  and  finished  as  in 
steels.  The  filtrates  and  washings  from  the  H2S  precipitation 
will  contain  all  of  the  nickel  and  a  little  iron.  Evaporate  this 
nitrate  and  washings  to  50  c.c.,  and  add  30  c.c.  of  cone,  nitric 
acid  to  oxidize  the  iron  and  destroy  any  remnant  of  the  H2S. 
Heat  with  a  cover  on  the  dish  until  all  action  is  over.  Then 
remove  the  cover,  cool,  add  30  c.c.  i  :  3  sulphuric  acid  and  evap- 
orate until  slight  fumes  of  sulphuric  anhydride  are  obtained. 
Cool;  add  50  c.c.  of  water;  and  filter  into  a  600  c.c.  beaker.  Add 
10  grams  of  citric  acid;  make  faintly  ammoniacal;  cool  and 
titrate  the  nickel  with  potassium  cyanide.  (See  the  author's 
modified  cyanide  method  for  Nickel  in  Steel,  page  164.) 

If  it  is  desired  to  determine  a  very  small  quantity  of  nickel 
in  steel,  about  0.3  per  cent  and  under,  weigh  10  or  15  grams  of 
sample  and  proceed  as  outlined,  getting  the  nickel  and  the  cop- 
per from  the  one  analysis.  If  the  nickel  content  is  likely  to  be 
under  o.i  per  cent,  it  is  convenient  to  use  10  grams  of  sample. 
If  it  is  in  excess  of  0.2  per  cent,  it  is  best  to  use  5  grams.  The 
precipitate  requires  that  considerable  paper  pulp  be  mixed  with 
it  to  secure  rapid  nitrations.  Wash  the  pulp,  etc.,  5  times 
with  water  containing  a  drop  of  sulphuric  acid  and  5  c.c.  of  the 
ferricyanide  solution  per  100  c.c.  of  water.  As  the  precipitate 
has  a  tendency,  at  times,  to  run  through  the  filter  when  first 
poured  on  it,  this  first  portion  of  the  filtrate  is  refiltered  until 
it  is  clear.  When  filtering  large  precipitates,  such  as  would  be 
obtained  from  50  mgs.  of  nickel,  it  is  expedient  to  use  2  funnels 
to  hasten  matters.  Nickel  up  to  50  mgs.  from  a  5  gram  weight 
of  sample,  or  10  mgs.  of  nickel  from  10  grams  of  sample,  can  be 
conveniently  precipitated  from  a  volume  of  500  c.c.  For  large 
amounts  of  nickel  in  steel,  —  i.e.,  0.50  per  cent  and  over,  —  the 
foregoing  method  is  not  nearly  so  rapid  as  the  one  described  on 
pages  164  to  175,  but  for  minute  quantities,  or  where  it  is  neces- 
sary to  first  remove  the  bulk  of  the  iron  or  the  vanadium  (much 


156  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

vanadium  in  solution  gives  ammoniacal  citrates  of  an  almost 
greenish  black  color,*  greatly  interfering  in  the  method  just 
referred  to),  it  is  a  useful  preliminary  to  the  cyanide  titration. 
There  would  seem  to  be  no  reason  why  the  ferricyanide  could 
not  be  applied,  with  suitable  modifications,  to  the  determination 
of  copper  and  nickel  in  ferro-manganese,  chrome  and  other  ferros 
and  metals  that  are  not  precipitated  by  this  useful  reagent 
(notably  aluminum)  in  acid  solution.  Manganese  is  precipitated 
by  the  ferricyanide  in  neutral  or  slightly  ammoniacal  solution  as 
quickly  as  are  copper,  nickel  and  zinc  in  slightly  acid  solution. 
(See  the  author's  volumetric  method  for  all  percentages  of  man- 
ganese above  2  per  cent,  page  193.) 

By  the  above  process  the  copper  and  nickel  can  be  determined, 
quantitatively,  in  the  same  analysis  with  the  chromium  and  the 
vanadium  when  the  copper  does  not  greatly  exceed  0.25  per 
cent:  Two  grams  are  taken  for  the  analysis.  The  nickel  and 
copper  ferricyanides  are  filtered  out  after  the  regular  titrations 
have  been  made  for  V  and  Cr.  Of  course  no  time  must  be  lost 
in  making  the  vanadium  part  of  the  titration,  as  copper  soon 
clouds  the  solution  after  the  addition  of  the  ferricyanide.  The 
author  uses  this  scheme  to  get  Cr,  V,  Ni  and  Cu  from  the  one 
analysis.  In  such  cases  the  titrated  solution  is  allowed  to  stand 
a  half  hour  before  filtering.  If  brown  nickel  ferricyanide  begins 
to  appear,  40  or  more  c.c.  of  potassium  ferricyanide  are  added 
and  filtration  is  delayed  for  an  hour. 

*  Read  page  174. 


CHAPTER  VIII. 

PART  III. 
COPPER  IN  METALLIC  COPPER  —  VOLUMETRIC. 

THE  author  regards  the  following  cyanide  titration  as  a  simple 
and  rapid  method  for  the  assay  of  metallic  copper.  Scarcely 
any  element  interferes  that  cannot  be  removed  by  precipitation 
with  H2S  in  hydrochloric  acid  solution.  If  carried  out  with 
proper  attention  to  details,  there  is  no  more  accurate  volumetric 
method  in  commercial  use.  It  is  essential  that  the  potassium 
cyanide  be  standardized  with  metallic  copper  of  known  copper 
content,  or  by  some  recrystallized  c.p.  salt  of  copper.  The 
metal  is  preferable,  and  is  put  through  every  analytical  detail 
that  is  applied  to  the  analysis  of  the  test. 

Operate  with  0.5  gram  of  the  test  and  of  the  standard  copper 
drillings,  running  both  standardizations  and  tests  parallel  with 
each  other.  Use  copper  of  99.8  per  cent  purity  for  standard- 
izing. The  drillings  are  dissolved  in  10  c.c.  1.20  nitric  acid, 
evaporated  to  5  c.c.,  filtered  from  any  tin,  etc.;  the  filter  washed 
with  water  containing  a  little  nitric  acid.  The  filtrate  and 
washings  are  evaporated  to  fumes  with  20  c.c.  i  :  3  sulphuric 
acid.  The  copper  sulphate  is  dissolved  in  water.  Any  lead  is 
removed  by  filtration  and  washed  with  water  containing  a  little 
sulphuric  acid.  Hydrogen  sulphide  is  then  passed  through  the 
nitrate,  in  a  volume  of  400  c.c.,  with  5  c.c.  excess  of  i  :  i  hydro- 
chloric acid  for  every  100  c.c.  of  water,  until  the  copper  has 
completely  separated  in  hot  solution.  Filter.  Wash  with  H2S 
water.  Return  filter  and  all  to  the  beaker.  Add  50  c.c.  of  1.20 
nitric  acid.  Give  standardizations  and  test  the  same  excess  of 
acid.  Warm  with  a  cover  on  until  copper  sulphide  is  dissolved. 
Filter  out  pulp.  Wash  thoroughly  with  water  containing  a 
little  1.20  nitric  acid.  Ignite  the  pulp;  dissolve  the  residue  in 

157 


158  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

1.20  nitric  acid;  add  the  solution  to  the  nitrate  and  washings; 
evaporate  to  20  c.c.  Add  1.5  grams  of  citric  acid  and  a  slight 
excess  of  sodium  carbonate.  Use  a  saturated,  filtered  solution 
of  the  carbonate  and  add  it  until  effervescence  ceases  entirely. 
Titrate  the  clear  blue  solution  with  a  standard  of  potassium 
cyanide  made  by  dissolving  22.434  grams  of  the  best  cyanide 
together  with  5  grams  of  potassium  hydroxide  in  distilled  water 
and  diluting  to  i  liter.  One  c.c.  of  this  standard  usually  equals 
about  0.00635  gram  of  copper;  but  this  value  should  always 
be  fixed  by  the  operator  himself,  in  the  manner  just  out- 
lined. The  following  modification  removes  uncertainty  as  to 
the  end  point  when  titrating  large  amounts  of  copper.  Add 
the  potassium  cyanide  as  usual  until  the  blue  color  is  almost 
gone.  Follow  with  additions  of  a  cyanide  standard  of  one-fifth 
strength  until  all  blue  tint  has  disappeared.*  Then  add  2  c.c. 
of  a  20  per  cent  solution  of  potassium  iodide  in  water;  then 
silver  nitrate  standard  until  a  slight  cloud  of  silver  iodide  is 
formed  as  in  Nickel  in  Steel.  (Chapter  IX.)  Now  add  about 
10  c.c.  excess  of  this  dilute  cyanide  standard.  Again  add  the 
silver  nitrate  standard  until  a  slight  milkiness  is  produced  in 
the  solution;  2.925  grams  of  silver  nitrate  are  dissolved  in  water 
and  diluted  to  500  c.c.  for  this  work. 

STANDARDIZATION. 

Suppose  0.500  gram  of  copper  drillings  of  99.8  per  cent  purity 
were  taken,  and  that  after  putting  this  metal  through  all  of  the 
foregoing  analytical  operations  the  following  data  were  obtained : 

First,  The  concentrated  cyanide  standard  required  to  nearly 
discharge  the  blue  color  equals  76.9  c.c. 

Second,  The  one-fifth  cyanide  standard  required  to  entirely 
discharge  the  blue  equals  26.8. 

Third,  The  silver  nitrate  solution  needed  to  produce  a  slight 

*  Now  wait  for  30  minutes  to  one  hour  to  give  the  KCN  and  the  copper  time 
to  completely  react  together  before  adding  the  KI  and  silver  nitrate  to  get  the 
excess  of  KCN.  This  should  be  done  because  the  blue  color  of  the  copper  disap- 
pears long  before  the  copper  and  the  KCN  have  entirely  ceased  to  combine. 


COPPER  IN  METALLIC   COPPER  —  VOLUMETRIC  159 

milkiness  in  the  solution,  after  the  blue  color  was  entirely  gone, 
equals  13.6  c.c. 

Fourth,  8.3  c.c.  of  silver  nitrate  were  used  to  produce  a  cloud- 
iness, again,  after  the  addition  of  11.3  c.c.  of  the  one-fifth  cyanide 
standard  in  excess,  or  i  c.c.  of  AgNOs  =  11.3  -s-  8.3,  or  1.36  c.c. 
of  the  one-fifth  cyanide  standard. 

Fifth,  Therefore  26.8  -  (13.6  X  1.36)  =  8.3,  or  the  amount 
of  one-fifth  cyanide  used  in  reaction  with  the  copper,  or  1.66  c.c. 
of  cone,  cyanide  to  be  added  to  76.9,  or  a  total  of  78.56  c.c.  of 
cone.  KCN  required  to  combine  with  the  0.500  gram  of  99.8  per 
cent  pure  copper.  Hence  i  c.c.  of  the  concentrated  cyanide 
standard  equals  0.499  ~*~  7^-5^  =  °-°°635,  or  i  c.c.  =  0.00635 
gram  of  copper.* 

Mr.  R.  M.  Clarke  of  this  laboratory  suggested  that  it  might 
be  an  advantage  to  use  silver  nitrate  to  obtain  a  more  exact  end 
point  instead  of  relying  on  the  disappearance  of  the  blue.  The 
analytical  details  are  the  author's. 

Further  Details. 

(a) 

Stir  the  copper  sulphide  into  small  particles  before  heating 
it  with  the  1.20  nitric  acid,  or  an  insoluble  black  lump  may  form. 
Then  heat  very  gently  at  first.  Keep  the  temperature  consid- 
erably below  100°  C.  at  all  times  to  prevent  occlusion  of  some  of 
the  copper  sulphide  by  the  liberated  sulphur,  and  the  formation 
of  a  black  insoluble  residue.  Pay  no  attention  to  any  milkiness 
that  may  appear  when  the  nitric  acid  solution  of  the  pulp  ash 
is  added  to  the  nitric  solution  of  the  main  sulphide. 


The  titration  can  be  accurately  accomplished,  omitting  the 
one-fifth  cyanide  standard:  Add  the  concentrated  standard 
until  the  blue  is  entirely  gone.f  Then  add  the  KI  indicator 
and  follow  with  the  silver  nitrate  until  a  very  slight  permanent 

*  The  author  now  uses  \  this  strength,  or  i  c.c.  equals  0.003175  gram  of  copper. 
A  100  c.c.  burette,  graduated  to  TVth  c.c.,  is  the  best  adapted  to  this  method. 
t  Then  pause  for  at  least  30  minutes  before  adding  the  Kl. 


160  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

cloudiness  occurs.  Next  drop  into  the  beaker  an  excess  of 
5  c.c.  of  the  cone,  cyanide.  Again  add  the  silver  nitrate  until 
a  very  faint  milkiness  is  once  more  apparent  that  does  not  dis- 
appear after  15  seconds  stirring. 


Further,  it  is  quite  important  to  add  the  cyanide,  while  dis- 
charging the  blue  color,  very  slowly  when  the  latter  begins  to 
fade:  Add  the  standard  three  drops  at  a  time;  then  stir  vigor- 
ously for  20  seconds.  If  the  blue  is  not  all  gone,  add  three  drops 
more  and  stir  again  for  a  period  of  twenty  seconds.  By  pro- 
ceeding in  this  way  and  making  the  titrations  in  small  volumes 
-  beginning  with  a  volume  of  not  over  100  c.c.  —  the  disap- 
pearance of  the  blue  affords  an  accurate  end  point  but  more 
experience  and  judgment  is  required  than  when  using  the  cyanide 
and  "  silver"  scheme.  After  thus  carefully  removing  the  blue 
tint  proceed  to  determine  the  actual  cyanide  used  by  means  of 
titration  (b). 

Calculations. 

(1)  0.500  gram  of  copper  required  84.2  c.c.  of  the  concen- 
trated cyanide  -to  just  discharge  the  blue. 

(2)  24.8  c.c.  of  the  AgNO3  standard  were  required  to  produce 
the  first  faint  cloudiness. 

(3)  21.9  c.c.  of  AgNOs  were  needed  to  produce  the  second 
faint  cloud  after  the  addition  of  5  c.c.  excess  of  the  cone.  KCN. 
Therefore  21.9  -f-  5  =  4.38,  or  i  c.c.  of  the  cyanide  equals  4.38 
c.c.  of  the  silver  nitrate  standard. 

(4)  From   (2)   and   (3)  we  have  24.8  -f-  4.38  =  5.66,  or  the 
excess  of  the  cyanide  standard  in  the  solution.     From  (i)  84.2  — 
5.66  =  78.54,  or  the  number  of  c.c.  of  the  cyanide  required  to 
combine  with  the  0.500  gram  of  copper.     There  is  always  an 
excess  of  the  cyanide  when  the  blue  color  is  gone,  but  the  re- 
action between  the  copper  and  the  KCN  is  not  usually  com- 
pleted for  at  least  30  minutes  after  the  disappearance  of  the 
blue. 


COPPER  IN  METALLIC   COPPER  —  VOLUMETRIC  161 


TlTRATION  OF  COPPER  IN  THE  PRESENCE  OF  OTHER 
METALS. 

If  the  solution  contains  3  grams  of  citric  acid  and  a  moderate 
excess  of  the  sodium  carbonate,  0.500  gram  of  copper  can  be 
accurately  titrated  in  the  presence  of  o.ioo  gram  of  zinc,  or  iron, 
or  0.050  gram  of  lead:  The  citric  acid  is  added  to  the  nitric 
solution  of  the  metals;  then  the  carbonate  until  effervescence 
ceases,  and  5  c.c.  in  excess.  The  volume  before  titration  should 
be  about  100  c.c.  When  much  iron  is  present  the  alkaline  solu- 
tion is  a  dark  green.  The  cyanide  standard  is  added  until  the 
green  is  gone  and  the  clear  amber  color  of  the  citrate  of  iron 
appears.  Then  determine  the  excess  of  the  cyanide  as  usual. 

As  much  as  o.ioo  gram  of  arsenic  can  be  present  without 
having  the  slightest  effect. 

The  author  made  entirely  successful  titrations  of  0.500  gram 
of  copper  dissolving  with  it  0.200  gram  of  antimony;  also  in 
the  presence  of  o.ioo  gram  of  cadmium.  The  end  point  given 
by  the  disappearance  of  bluish  tints  from  the  white  antimony 
oxides  and  cadmium  carbonate  was  noted.  This  end  point  was 
obtained  as  in  (c).  The  precipitates  were  then  removed  by 
nitration  through  double  niters,  and  the  excess  of  cyanide  was 
determined  in  the  nitrate  and  washings  in  the  usual  way  with 
silver  nitrate.  The  precipitates  had  to  be  poured  through  the 
filters  several  times  to  secure  clear  nitrates.  The  precipitates 
were  washed  ten  times  with  dilute  sodium  carbonate  water. 

When  titrating  copper  in  the  presence  of  0.200  gram  of  bis- 
muth the  disappearance  of  the  blue  was  taken  as  the  end  point, 
as  the  basic  bismuth  clouded  the  solution.  With  but  o.ioo 
gram  of  bismuth  in  solution  the  entire  titration,  as  outlined  in 
(6),  was  successfully  carried  through  before  the  solution  was 
perceptibly  clouded. 

Large  quantities  of  manganese  interfere  with  the  titration  of 
copper  only  in  so  far  as  dark  colored  solutions  are  formed  when 
the  cyanide  is  added,  thereby  obscuring  somewhat  the  end 
point  between  the  cyanide  and  the  " silver  nitrate."  More  citric 


162  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

acid  is  required.  Add  to  the  standardization  about  as  much 
manganese  as  there  is  likely  to  be  in  the  copper  that  is  to  be 
assayed.  Use  at  least  6  grams  of  citric  acid  per  0.200  gram 
of  Mn. 

PRECIPITATION  BY  ALUMINUM. 

When  using  this  well-known  method  one  can  proceed  as  at 
first  described  until  the  nitrate  and  washings  from  the  lead  sul- 
phate are  obtained.  Evaporate  the  former  to  20  c.c.;  add 
10  c.c.  i  :  3  sulphuric  acid  and  a  piece  of  aluminum  i^  inch 
square  by  TXg  inch  thick.  Heat  nearly  to  boiling  for  30  minutes, 
or  until  the  solution  is  colorless.  Remove  the  aluminum  and 
decant  the  solution  through  a  9  cm.  filter;  wash  the  filter  15 
times  with  water  containing  a  few  drops  of  i  :  3  H2SO4.  Return 
the  filter  to  the  150  c.c.  beaker  in  which  the  precipitation  was 
made. 

The  filtrate  and  washings  from  the  metallic  copper  should  be 
tested  with  H2S  and,  if  a  brown  coloration  is  obtained,  continue 
to  pass  the  gas  until  the  small  precipitate  of  copper  collects. 
Filter  it  out;  wash  it  with  H2S  water  containing  a  drop  or  two 
of  i  :  3  H2SO4.  Put  this  filter  in  the  same  beaker  with  the 
metal;  add  20  c.c.  1.20  nitric  acid;  heat  below  boiling  until  the 
copper  is  dissolved;  filter  off  the  pulp;  wash  it  40  times  with 
water  containing  a  little  1.20  nitric  acid;  evaporate  the  filtrate 
and  washings  to  20  c.c.  in  a  600  c.c.  beaker  and  titrate  the  copper 
with  cyanide  and  "  silver  nitrate."  Hold  the  copper  solution  about 
one  hour  after  discharging  the  blue  with  cyanide  and  before  titrating 
with  the  cyanide  and  silver  nitrate. 

The  author  found  that  owing  to  the  slowness  of  the  reaction 
between  the  KCN  standard  and  the  copper  ammonium  com- 
pound that  the  above  precaution  of  holding  the  solution  for  an 
hour  after  discharging  the  blue  of  the  copper,  and  then,  after 
the  said  interval,  determining  the  excess  of  cyanide  in  the  man- 
ner given  on  page  159,  (b)  and  (c),is  an  essential  one.  It  gives 
such  satisfactory  results  that  he  prefers  this  volumetric  method 
to  all  others  for  the  determination  of  copper.  As  the  chem- 


COPPER  IN  METALLIC   COPPER  —  VOLUMETRIC  163 

ist  usually  has  several  titrations  of  copper  to  make,  at  the  same 
time,  no  delay  of  any  consequence  results,  as  a  number  of  tests 
can  be  given  the  first  part  of  the  titration  for  the'  discharge  of 
the  blue  color,  and,  by  the  time  the  blue  has  been  discharged 
from  the  last  test,  the  first  one  has  been  standing  the  required 
time.  It  can  then  be  at  once  finished  with  the  cyanide  and 
silver  nitrate.  The  author  now  uses  and  recommends  one-half 
the  strength  of  cyanide  standard  given  on  page  159,  that  is,  i  c.c. 
equals  0.003175  gram  of  copper. 


CHAPTER  IX. 

PART  I. 

*  THE  RAPID  DETERMINATION  OF  NICKEL  IN  THE  PRESENCE 
OF  CHROMIUM,  IRON  AND  MANGANESE. 

IN  applying  the  method  of  T.  Moore  f  to  the  determination 
of  nickel  in  steel,  the  directions  given  on  page  183,  Analysis  of 
Steel  Works  Materials  by  Brearley  and  Ibbotson,  were  followed: 
One  gram  of  steel  was  dissolved  in  a  150  c.c.  beaker  with  10  c.c. 
of  concentrated  hydrochloric  acid  diluted  with  an  equal  volume 
of  water. 

When  action  ceased  10  c.c.  of  nitric  acid  (1.20)  were  added, 
and  the  contents  of  the  beaker  were  boiled  to  about  one-half. 
1 6  c.c.  of  dilute  sulphuric  acid  were  poured  into  the  solution 
and  also  3  grams  of  powdered  citric  acid.  The  solution  was 
stirred  until  the  citric  acid  was  dissolved,  transferred  to  a  600  c.c. 
beaker,  and  rendered  faintly  but  distinctly  ammoniacal. 

The  nickel  was  titrated  with  a  standard  solution  of  potassium 
cyanide,  using  a  measured  amount  of  standard  silver  nitrate 
and  2  c.c.  of  a  20  per  cent  solution  of  potassium  iodide  as  an 

Note:  For  Brunck's  Dimethylglyoxime  Method  for  Nickel  and  the  author's 
modification  of  this  separation,  see  page  175. 

indicator.  The  deep  red  color  of  the-  citrate  of  iron  greatly  ob- 
scures the  end  point.  The  authors  complain  of  this  color  and 
recommend  the  use  of  a  condensing  lens  to  cast  a  beam  of  light 
through  the  darkness.  In  the  presence  of  chromium  the  writer 

*  [Reprinted  from  the  Journal  of  the  American  Chemical  Society  (with  additions), 
Vol.  XXIX,  No.  8,  August,  1907.] 
t  Chemical  News,  72,  92. 

164 


DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM      165 

found  that  a  still  more  somber  gloom  settled  down  over  the  close 
of  the  reaction.  The  authors  mentioned  also  state  that  this 
element  retards  the  union  of  the  cyanide  and  the  nickel,  causing 
the  recurrence  of  the  cloud  of  silver  iodide. 

After  struggling  with  the  process  for  some  time  and  always 
carefully  separating  the  chromium,  and  with  it  the  iron,  in 
chrome  steels,  an  attempt  was  made  to  dispel  the  darkness  and 
also  to  avoid  these  tedious  separations:  Less  citric  acid  per 
gram  of  steel  was  taken,  and  the  dark  red  shaded  to  blackness. 

Naturally,  the  amount  of  citric  acid  per  gram  of  steel  was  then 
increased,  that  is,  6  grams  of  citric  acid  per  gram  of  steel  were 
used,  and  a  marked  improvement  was  noted.  Still  more  citric 
acid  caused  a  complete  lifting  of  the  shadows. 

The  following  modified  procedure  was  finally  adopted  for 
nickel  steels  after  having  been  thoroughly  tested  with  plain 
carbon  steels  to  which  known  amounts  of  nickel  had  been  added : 
Dissolve  i  gram  of  steel  drillings  in  a  150  c.c.  beaker  with  20  c.c. 
of  hydrochloric  acid  (i  :  i).  When  action  ceases  add  10  c.c.  of 
nitric  acid  (1.20). 

Reduce  the  volume  of  the  solution  to  about  15  c.c.,  keeping 
the  beaker  covered  during  the  boiling.  Remove  the  beaker  from 
the  fire  and  pour  into  it  8  c.c.  of  cone,  sulphuric  acid  diluted 
with  24  c.c.  of  water.  The  presence  of  the  sulphuric  acid  is 
essential  to  a  sharp  end  reaction  between  the  cyanide  standard 
and  the  silver  iodide  in  the  subsequent  titration. 

Transfer  the  contents  of  the  beaker  to  one  of  600  c.c.  capacity 
containing  twelve  grams  of  powdered  citric  acid.  Stir  until  the 
citric  acid  is  dissolved.  Render  this  solution  faintly  but  dis- 
tinctly alkaline  with  ammonia,  using  one  part  of  concentrated 
ammonia  diluted  with  one  part  of  water.  A  large  excess  of 
ammonia  causes  low  results.  Stand  the  beaker  in  running 
water  until  it  is  cold.  The  volume  of  the  solution  should  now 
be  about  300  c.c.  Much  larger  volumes  than  300  c.c.  should  be 
avoided,  as  great  dilution  retards  the  end  point,  causing  the 
cloud  of  silver  iodide  to  disappear  and  then  to  reappear  again 
in  a  few  minutes. 


166  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  faintly  ammoniacal  condition  *  can  be  easily  controlled  by 
adding  the  ammonia  rather  slowly  and  noting  the  changes  of 
color  that  ensue:  The  first  change  is  to  amber,  then  to  yellow- 
ish green,  then  to  distinct  green,  then  to  a  light  shade  of  green, 
then  to  a  yellow  almost  matching  the  yellow  color  of  the  acid 
solution.  The  reappearance  of  the  yellow  tint  indicates  that 
alkalinity  is  nearly  attained. 

A  little  more  ammonia  now  causes  a  brownish  shade,  which 
is  evidence  that  the  ammonia  is  in  slight  excess.  The  moder- 
ately alkaline  citrate  of  iron  obtained  in  the  proportion  of  i  gram 
of  iron  to  12  grams  of  the  citric  acid  yields  a  bright  greenish 
yellow  solution  in  plain  nickel  steels  instead  of  being  of  a  dense 
dark  red  shade. 

To  the  cold  solution  two  c.c.  of  a  20  per  cent  solution  of  po- 
tassium iodide  are  added.  From  a  50  c.c.  burette  a  standard 
solution  of  silver  nitrate  is  dropped  into  the  same  beaker,  pro- 
ducing with  the  iodide  a  white  turbidity.  The  standard  potas- 
sium cyanide  is  added  with  constant  stirring  until  the  cloud  of 
silver  iodide  just  disappears,  which  it  does  on  being  converted 
into  silver  cyanide.  Nickel  cyanide  is  first  formed,  and  then 
the  silver  cyanide  is  produced: 

(1)  Ni(NO3)2  +  4  KCN  =  Ni(CN)2  •  2  KCN  +  2  KNO3. 

(2)  AgN03  +  2  KCN  =  AgCN  -  KCN  +  KN03. 

If  the  directions  are  followed  as  given,  the  titration  can  be 
accomplished  at  almost  the  full  speed  of  the  burette.  If  the 
titrated  solutions  are  permitted  to  remain  in  the  open  beakers 
for  a  time,  a  film  usually  appears  on  the  surface  of  the  liquid. 
No  account  is  taken  of  it,  as  its  presence  is  most  likely  due  to  a 
superficial  loss  of  ammonia.  The  reactions  are  always  found  to 
be  completed  when  the  body  of  the  solution  is  freed  of  the 
iodide  precipitate. 

*  One  can,  also,  use  litmus  paper;  add  ammonia,  drop  by  drop,  until  i  drop  of 
i  :  i  ammonia  just  turns  the  red  litmus  blue,  then  add  10  drops  excess  of  the 
ammonia  and  no  more.  A  person  with  the  average  sense  of  smell  can  add  am- 
monia until  a  slight  sweet  smell  is  obtained  and  then  the  10  drops  of  excess  with 
better  success  than  with  the  use  of  litmus. 


DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM     167 

Standards.  From  the  equations  as  given,  5.85  grams  of  silver 
nitrate  are  equivalent  to  4.4868  grams  of  potassium  cyanide. 
This  weight  of  cyanide  dissolved  in  i  liter  of  water  gives  a 
value  of  i  c.c.  equals  about  0.001014  gram  of  nickel. 

As  comparatively  little  silver  nitrate  is  needed  with  each 
analysis,  it  is  not  advisable  to  prepare  more  than  a  half  liter 
of  the  water  solution  of  this  salt,  using  2.925  grams  per  500  c.c. 
of  distilled  water. 

The  potassium  cyanide  standard  should  contain  about  5 
grams  of  potassium  hydroxide  to  the  liter,  which  renders  it 
quite  permanent.  The  solutions  are  readily  standardized  by 
applying  them  to  a  plain  steel  to  which  a  known  amount  of 
nickel  has  been  added.  The  chemically  pure  double  sulphate 
of  nickel  and  ammonium  is  a  convenient  standardizing  medium. 
For  example,  0.2  gram  and  0.25  gram  of  the  double  sulphate 
can  be  weighed  into  150  c.c.  beakers  together  with  i  gram  of 
plain  carbon  steel  drillings. 

This  mixture  is  then  put  through  all  of  the  foregoing  manip- 
ulations and  titrated  with  the  cyanide  solution  that  is  to  be 
standardized.  The  number  of  c.c.  of  the  silver  nitrate  and  of 
the  potassium  cyanide  solution  used  in  this  titration  are  noted. 
An  excess  of  10  c.c.  of  the  cyanide  is  now  added  and  in  turn 
titrated  with  the  silver  nitrate  solution  until  a  distinct  cloud  of 
silver  iodide  is  produced.  This  second  titration  gives  the  rela- 
tion between  the  silver  solution  and  the  cyanide. 

An  actual  case  will  illustrate  the  calculations:  In  sample 
No.  3477,  1.7  c.c.  of  standard  silver  nitrate  solution  were  re- 
quired to  produce  a  distinct  turbidity  and  also  to  combine  with 
any  excess  of  potassium  cyanide  standard.  In  all,  35  c.c.  of  the 
cyanide  were  consumed  in  the  titration.  When  the  cloud  of 
silver  iodide  had  just  been  dispelled,  an  excess  of  9.8  c.c.  of 
cyanide  was  allowed  to  flow  into  the  clear  solution.  Just  10.1 
c.c.  of  silver  nitrate  standard  were  needed  to  produce  a  reap- 
pearance of  the  cloudiness.  Therefore  9.8  -4-  10.1  =  0.97,  or 
0.97  c.c.  of  cyanide  standard  solution  equals  i  c.c.  of  silver 
nitrate.  Hence  instead  of  deducting  1.7  c.c.  from  35  c.c., 


i68 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


1.7  X  0.97  or  1.65  c.c.  were  deducted,  leaving  33.35  c.c.  of  cya- 
nide combined  with  the  nickel  in  this  steel. 

To  a  plain  carbon  steel  0.200  gram  .of  double  sulphate  of  nickel 
and  ammonium  were  added  put  through  all  of  the  steps  of  a 
regular  analysis.  This  mixture  required  28.75  c-c-  °f  cyanide. 
The  nickel  salt  contains  14.86  per  cent  of  nickel,  or  0.200  X 
0.1486  =  0.02972  gram  of  nickel  were  present.  Hence  0.02972 
-=-  28.75  =  0.00103,  or  i  c.c.  of  standard  cyanide  solution  is 
equivalent  to  0.00103  gram  of  nickel.  No.  3477,  as  has  been 
stated,  required  33.35  c.c.  of  the  cyanide  standard,  and  therefore 
contains  0.00103  X  33.35  =  0.03435,  or  0.03435  gram  of  nickel, 
or  3.435  per  cent. 

Chromium-nickel  Steels.  When  chromium  is  present  proceed 
exactly  as  in  plain  nickel  steels  except  that  twenty-four  grams 
of  citric  acid  per  gram  of  steel  are  used.  This  proportion  of 
citric  acid  is  adequate  to  render  the  end  point  quite  as  easy  to 
see  as  in  ordinary  nickel  steels.  The  action  is  prompt  and  free 
from  recurrence  of  turbidity.  Of  course,  cloudiness  through 
the  entire  solution  will  occur,  as  the  ammonia  is  dissipated  from 
it,  after  it  has  stood  for  some  time  in  an  open  beaker. 

The  tabulation  (i)  that  follows  furnishes  satisfactory  proof 
that  chromium  does  not  interfere  with  the  successful  technical 
estimation  of  nickel  in  its  presence: 

TABLE   i. 


Sample. 

No  Chromium  Added. 
Nickel  Found, 
Per  Cent. 

Per  Cent  of  Chro- 
mium Added  to  a 
Portion  of  the 
Same  Steels. 

Nickel  Found  after  the 
Addition  of  Varying 
Amounts  of  Chromium. 

Number. 

525 

5-09 

4 

5.10 

2991 

4-44 

2 

4-45 

7239 

3-24 

I 

3-28 

3017 

4.96 

I 

5-03 

612 

3-47 

0-5 

3-47 

7273 

3-29 

I 

3-3i 

622 

3-56 

0-5 

3.56 

7288 

3-32 

2 

3-41 

7289 

3-n 

2 

3-i6 

663 

3-57 

6 

3-59 

2991 

4-44 

3 

4-47 

DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM     169 


The  chromium  was  introduced  in  the  form  of  recrystallized 
chemically  pure  potassium  dichromate.  The  dichromate  crys- 
tals were  mixed  with  a  weighed  amount  of  nickel  steel  drillings 
before  the  addition  of  the  20  c.c.  of  hydrochloric  acid.  The 
combined  action  of  the  nascent  hydrogen  from  the  steel,  the 
excess  of  boiling  hydrochloric  acid  and  the  ferrous  chloride 
reduced  the  chromate  to  chromic  chloride,  thus  duplicating  the 
conditions  found  when  a  chromium-nickel  is  similarly  treated. 
Determination  by  this  modification  of  the  cyanide  method 
can  be  finished  in  from  45  to  50  minutes,  either  in  the  presence  or 
absence  of  any  per  cent  of  chromium  likely  to  be  met  with  in 
steels  or  alloys  soluble  in  the  acids  given.  In  this  laboratory 
duplicate  determinations  in  nickel  or  nickel-chromium  steels 
are  made  in  the  time  just  specified.  By  the  process  one  can 
decide  in  a  few  minutes  whether  or  not  nickel  is  present  in  a 
given  steel  and  just  how  much.  Tungsten,  if  present,  does  not 
interfere,  appreciably,  as  has  been  noted  by  the  authors  men- 
tioned in  this  article.  The  writer  had  two  different  amounts  of 
nickel  added  to  a  steel  containing  several  per  cent  of  chromium 
and  from  16  to  17  per  cent  of  tungsten.  This  steel  was  then 
carried  through  exactly  as  though  no  tungsten  or  chromium 
were  present,  using  the  method  as  given  for  chromium-nickel 
steels. 


Nickel  Added, 
Gram. 

Nickel  Found. 

0.0297 
0.03715 

None 

0.0299 
0.0372 
o  .  0006 

Table  2  demonstrates  that  neither  vanadium,  tungsten,  chro- 
mium, nor  molybdenum,  when  present  in  the  amounts  given, 
interferes  appreciably  in  technical  analysis.  These  amounts 
represent  extreme  cases,  especially  for  the  vanadium,  it  being 
equivalent  in  one  instance  to  3.5  per  cent  V  when  one  gram  of 
steel  is  taken. 


1 7o 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


Tests  were  then  made  in  the  same  manner  in  the  presence  of 
molybdenum  and  vanadium  as  follows: 


TABLE   2. 


Name. 

Kind  of  Steel  or  Mixture. 

Nickel 
Added, 
Gram. 

Nickel 
Found, 
Gram. 

J   R.  Steel 

Contains  TO^  -4-  Mo. 

O  O2Q7 

O  O2Qs 

Do. 

do. 

O  O222 

o  0223 

Do.    . 

.do. 

None 

O   OOO  2 

Bxx-i73  steel  
Do  

Contains  4%  Mo  and  4%  Cr  
....do  

0.0223 
0.0297 

O.O222 
0.0296 

Do 

do 

None 

o  0004 

A  mixture 

o  920  gram  of  steel 

o  0207 

o  0298 

o  030  gram  of  nickel. 

o  018  gram  of  vanadium  . 

A  mixture 

o  840  gram  of  steel.    .               .    . 

0.0223 

O.O227 

o  .  022  gram  of  nickel  

0.035  gram  of  vanadium  

A  blank  

i  .  ooo  gram  of  steel  
o  035  gram  of  vanadium 

None 

0.0008 

As  copper  also  forms  cyanides,  its  presence  would  cause  results 
to  be  too  high,  but  copper  is  avoided  in  good  steel  making.  Its 
presence  is  unlikely  in  greater  amounts  than  0.06  per  cent, 
although  the  writer,  on  one  occasion,  found  as  much  as  0.25 
per  cent  in  a  low  carbon  steel,  not  a  crucible  steel,  however. 
Crucible  steel  rarely  contains  over  0.04  per  cent  copper.  The 
choice  brands  are  under  0.03  per  cent  in  copper. 

Wishing  to  test  the  extent  to  which  nickel  could  be  titrated 
in  the  presence  of  large  percentages  of  chromium,  iron  being 
also  present,  the  mixtures  as  given  in  Table  3  were  titrated  with 
potassium  cyanide.  The  various  salts  were  weighed  into  150  c.c. 
beakers,  together  with  the  proper  amounts  of  steel  drillings. 
The  same  proportions  of  hydrochloric,  nitric,  citric  and  sul- 
phuric acids  were  employed  as  are  herein  given  for  nickel- 
chromium-steels,  and  were  applied  in  the  same  manner. 

A  sufficient  quantity  of  the  salts  of  chromium  and  nickel,  and 
of  the  steel  drillings,  were  taken  to  give  a  total  of  one-half  gram 
of  metals  in  the  mixture. 


DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM     171 


Double  sulphate  of  nickel  and  ammonium  ((NH^SC^  •  NiS04  • 
6  H20),  potassium  dichromate  and  steel  drillings  free  from  nickel 
were  used  as  sources  of  nickel,  chromium  and  iron,  respectively. 

To  obtain  the  nickel  value  of  the  cyanide  standard  under  con- 
ditions similar  to  those  existing  in  the  mixtures  tested,  stand- 
ardizing mixtures  of  these  salts  were  prepared  varying  from  the 
mixtures  tested  as  much  as  i  per  cent  to  20  per  cent  in  the  differ- 
ent constituents. 

For  mixtures  exceeding  10  per  cent  of  nickel  a  standard 
cyanide  solution  with  a  nickel  value  of  i  c.c.  =  0.0031  gram  of 
nickel  was  used.  The  standardizing  mixtures  were  dissolved 
and  treated  exactly  as  the  mixtures  tested.  The  same  method 
of  standardization  was  observed  in  the  work  recorded  in  Table  4. 

TABLE   *. 


Per  Cent  of  Metals. 

Gram  of  Nickel. 

Ni. 

Cr. 

Fe. 

Added. 

Found. 

30 

40 

30 

0.1499 

0.1494;      0.1495 

60 

2O 

20 

0.2999 

0.3003;      0.2989 

20 

40 

40 

o.  1029 

O.  IO22 

5 

QO 

5 

o  .  0250 

0.0248;       O.O244 

4 

92 

4 

O.O2OO 

O.OI99 

i-5 

95 

3-5 

o  .  00749 

0.00805;     0.00822 

0-5 

99 

0-5 

O.OO249 

(  0.00225;     0.00243 

I  0.00247;     0.0026 

o 

98.9 

i  .0 

None 

None 

Table  3  demonstrates  that  nickel  may  be  estimated  by  the 
foregoing  modified  cyanide  process,  using  the  proportions  of 
citric  acid  as  given,  with  sufficient  accuracy  for  works  analysis, 
and  indeed  for  most  practical  purposes,  even  when  the  percen- 
tage of  chromium  is  as  much  as  99  per  cent,  and  the  nickel 
content  is  but  one-half  of  one  per  cent. 

!  The  titration  of  the  mixtures  given  in  Table  3,  and  contain- 
ing  the   larger   amounts   of   chromium,    requires   considerable 
*  Read  the  determination  of  nickel  in  the  presence  of  much  chromium,  page  174. 


172  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

practice  on  the  part  of  the  operator.  The  work  should  always 
be  carried  out  in  duplicate.  The  disappearance  of  the  cloudi- 
ness in  the  presence  of  o.ioo  to  0.450  gram  of  chromium  in  a 
volume  of  350  to  400  c.c.  is  much  more  exactly  observed  when 
the  mixture  containing  the  iodide  cloud  is  compared,  from  time 
to  time,  with  a  similar  mixture  which  is  perfectly  free  of  this 
milky  turbidity.  The  dilution  of  the  deep  purple,  or  wine  color, 
of  these  ammoniacal  mixtures  of  citrates  to  more  than  300  to 
400  c.c.  renders  the  end  point  but  slightly  more  distinct,  and  has 
the  great  objection  of  retarding  the  reaction  between  the  cyanide 
and  the  nickel.  The  increase  above  24  grams  of  citric  acid,  in 
the  solution,  even  to  the  extent  of  adding  60  grams  of  citric 
acid,  did  not  relieve  the  density  of  color  to  any  perceptible 
extent. 

When  titrating  with  a  standard,  i  c.c.  of  cyanide  =  0.0031 
gram  of  nickel  (three  times  the  strength  used  for  steels),  do  not 
also  increase  the  strength  of  the  silver  standard  to  equal  it,  but 
still  retain  the  silver  nitrate  standard  as  given  for  steels.  A 
silver  nitrate  solution  sufficiently  concentrated  to  be  equivalent, 
volume  for  volume,  to  the  cyanide  standard  (i  c.c.  =  0.0031 
gram  of  nickel)  on  being  dropped  into  the  solution  containing 
the  potassium  iodide,  does  not  produce  the  usual  opalescence, 
alone,  but  forms  curds  of  iodide  that  do  not  readily  combine 
with  the  cyanide  standard.  The  end  point  is  reached  and  the 
main  body  of  the  solution  is  free  of  cloud  while  curds  of  silver 
iodide  still  lie  on  the  bottom  of  the  beaker.  The  weaker  silver 
nitrate  standard,  or  5.85  grams  of  silver  nitrate  to  the  liter, 
produces  with  the  potassium  iodide  a  finely  divided  cloud  of 
precipitate  that  combines  promptly  with  the  strong  cyanide 
standard,  giving  a  sharp  end  point.  Weigh,  therefore,  2.925 
grams  of  silver  nitrate,  diluting  to  500  c.c.,  and  13.4604  grams 
of  the  best  grade  of  potassium  cyanide,  diluting  to  1000  c.c.,  for 
titrations  of  solutions  containing  from  o.ioo  to  0.300  gram  of 
nickel;  i  c.c.  of  this  silver  nitrate  solution  should  be  equivalent 
to  ^  c.c.  of  the  concentrated  cyanide  standard  (i  c.c.  cyanide  = 
0.0031  d=  grams  of  nickel). 


DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM     173 


The  titration  of  nickel  by  potassium  cyanide  in  mixtures 
containing  large  percentages  of  manganese  with  varying  amounts 
of  chromium  and  iron  was  also  tried. 

As  in  the  experiments  outlined  in  Table  3,  mixtures  were  pre- 
pared to  contain  one-half  gram  of  metallic  substances.  The 
same  nickel  and  chromium  salts  were  employed.  Potassium 
permanganate  crystals  supplied  the  manganese. 

The  crystals  of  double  sulphate  of  nickel  and  ammonium,  po- 
tassium dichromate  and  potassium  permanganate  were  weighed 
into  a  150  c.c.  beaker  with  the  steel  drillings.  To  this  were 
added  20  c.c.  of  dilute  hydrochloric  acid.  The  contents  of  the 
beaker  were  then  boiled,  after  the  first  action  was  completed, 
until  the  chromate  and  permanganate  were  reduced.  An  addi- 
tion of  10  c.c.  of  nitric  acid  (1.20)  followed,  and  the  analysis 
was  carried  out  exactly  as  given  for  chromium-nickel  steels, 
using  24  grams  of  citric  acid.  The  results  obtained  are  given 
in  Table  4.  Sulphuric  acid  was  added  as  in  the  process  for 
steels. 

TABLE  4. 


Per  cent  of  Metals. 

Gram  of  Nickel. 

Ni. 

Mn. 

Cr. 

Fe. 

Added. 

Found. 

41 
20.  6 

15 
i-5 

20 
40 
60 
95-5 

10 

20 

15 

I 

30 
2O 
10 

2 

o.  2059 
o.  1029 
0.0750 
o  .  00749 

o  .  2058 
0.10228 
0.0752 
0.00762 

0.25 

94-9 
94-9 

2 

2 

2.Q 

4 

0.00124 

None 

O.OOI22 
O.OOOO6 

Table  4  gives  evidence  of  the  fact  that  nickel  can  be  accurately 
determined  in  the  presence  of  large  percentages  of  chromium 
and  manganese,  if  the  conditions  herein  given  are  carefully  ob- 
served. In  the  hands  of  a  practiced  operator  no  difficulty  was 
experienced  in  the  analysis  when  as  much  as  95  per  cent  of 
manganese  was  in  solution  with  but  0.25  per  cent  of  nickel. 

Where  large  amounts  of  reduced  chromium  are  encountered 


174  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

with  nickel,  the  latter  can  be  titrated  to  a  better  advantage  by 
boiling  the  sulphuric  acid  solution  of  the  sample  with  an  excess 
of  KMnC>4 ;  filtering  out  the  manganese  oxide  and  then  proceed- 
ing with  the  addition  of  the  citric  acid,  etc.  (see  E.  D.  Campbell 
and  W.  Arthur,  J.  Am.  Chem.  Soc.,  30,  1116-20,  July,  1908). 
There  is  not  the  slightest  need  for  all  this  extra  work  for  any 
amount  of  chromium  ever  found  in  steels,  unless  it  is  desired  to 
determine  this  element  in  the  same  analysis  with  the  nickel. 
In  that  event  use  4  grams  of  steel  and  proceed  as  in  CrV  steels 
(Chapter  II) ;  and,  when  the  solution  is  ready  for  the  titrations, 
divide  it  in  two  equal  portions.  Finish  one  portion  for  Cr  and  V 
by  the  method  in  Chapter  II.  Finish  ONE-HALF  of  the  other 
part  for  nickel,  adding  citric  acid,  etc.  This  procedure  avoids 
the  reoxidizing  and  refiltering  resorted  to  by  Messrs.  Campbell 
and  Arthur;  and  also  any  necessity  of  making  the  objection- 
able spot  tests.  It  affords  an  easy  way  of  getting  Cr,  V  and  Ni 
from  the  one  analysis. 

Add  the  citric  acid  after  neutralizing  the  free  acid  when  large 
amounts  of  chromium  or  vanadium  are  present  with  the  nickel. 

By  first  performing  the  neutralization  before  adding  the 
citric  acid,  the  latter  is  prevented  from  reducing  the  vanadium 
or  chromium  and,  in  this  way,  the  intense  dark  colors  are  elimi- 
nated. It  is  still  better  to  not  only  neutralize  the  free  acid  of 
the  chromic  acid-nickel  or  the  vanadic  acid-nickel  solution,  but  to 
also  convert  the  citric  acid  to  ammonium  citrate  before  adding 
this  organic  compound  to  the  almost  or  entirely  neutral  solu- 
tion of  the  nickel  and  chrome,  or  nickel  and  vanadium.  This 
of  course  applies  -only  to  the  filtrate  after  boiling  with  perman- 
ganate to  oxidize  the  vanadium  to  the  vanadic  and  the  chro- 
mium to  the  chromic  state.  This  oxidation  is  highly  to  be 
recommended  when  large  amounts  of  vanadium  or  chromium 
are  present. 

After  adding  the  ammonium  citrate,  the  usual  amount  of 
excess  of  ammonia  is  introduced  and  the  citrate  will  gradually 
dissolve  the  iron  hydroxide  after  prolonged  stirring. 


DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM     175 

THE  COMPLETE  ANALYSIS  OF  "30  PER  CENT"  NICKEL 

STEEL. 

Iron.  Dissolve  0.3  or  0.45  gram  of  sample  in  30  c.c.  of  1.20 
nitric  acid  in  a  porcelain  dish,  and  when  the  action  is  over,  evap- 
orate the  solution  to  dryness;  ignite  the  bottom  of  the  dish  to  a 
dull  red  to  destroy  the  carbon;  cool;  dissolve  in  20  c.c.  of  cone. 
HC1  and  finish  as  in  iron  ore  by  reduction  with  stannous  chlor- 
ide and  titration  with  potassium  dichr ornate  standard.  The 
nickel  does  not  interfere  except  to  turn  the  spot  tests  cloudy, 
but  not  so  quickly  but  that  the  end  point  can  be  seen.  0.45 
gram  of  sample  required  53.2  c.c.  of  the  standard;  53.2  times 
0.00565  divided  by  0.45  times  100  equals  66.7  per  cent  iron. 

STANDARDIZATION  IN  THE  PRESENCE  OF  NICKEL. 

Dissolve  0.300  gram  of  the  U.  S.  Bureau  Sibley  iron  ore  to- 
gether with  i. oo  gram  of  double  sulphate  of  nickel  and  ammo- 
nia, as  above,  and  put  it  through  all  of  the  operations  as  given.. 
Titrate  it  with  the  regular  dichromate  standard  as  used  for  iron 
ore  (9.8  grams  of  recrystallized  K2Cr2O7  dissolved  in  water  and 
diluted  to  2000  c.c.).  This  gives  a  factor  of  i  c.c.  equals  0.00565 
gram  of  iron,  that  is,  36.7  c.c.  of  the  standard  were  used,  hence 
0.300  times  0.692  divided  by  36.7  equals  0.00565. 

The  carbon,  manganese,  etc.,  were  determined  as  in  plain 

steels. 

RESULTS. 


Per  cent. 

Carbon o .  20 

Manganese o .  74 

Phosphorus 0.025 

Sulphur o .  025 


Per  cent. 


Silicon 0.125 

Nickel 32.27 

Iron 66.75 


BRUNCK'S  METHOD  FOR  NICKEL  IN  STEEL. 

This  method  is  supposed  to  separate  nickel  from  iron,  chro- 
mium, zinc,  manganese  and  cobalt.  The  presence  of  a  large 
quantity  of  manganese  requires  the  precipitation  to  be  made  from 
acetic  solution.  The  procedure  for  steel  is  to  dissolve  from 


176  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

0.5  to  0.6  gram  in  10  c.c.  of  i  :  i  HC1  with  heat.  Oxidize  with 
nitric  acid;  boil  off  the  red  fumes;  silicon  is  not  removed;  it 
would  seem  to  the  writer  that  it  would  be  safer  in  some  steels 
to  remove  the  silicon  by  evaporation  to  dry  ness. 

Add  from  2  to  ,3  grams  of  citric  acid  and  make  the  solution 
slightly  ammoniacal  to  see  if  any  precipitation  occurs.  If  the  so- 
lution remains  clear,  add  HC1  drop  by  drop  until  slight  acidity  is 
attained.  Heat  to  near  boiling;  add  20  c.c.  of  a  i  per  cent  solu- 
tion of  dime  thy  Iglyoxim  in  alcohol.  Now  drop  in  ammonia  to 
slight  alkalinity.  Let  stand  for  one  hour  and  filter  hot.  Wash 
with  water.  The  red  precipitate  is  caught  on  a  Gooch  or  Munroe 
crucible  and,  after  being  thoroughly  washed,  is  dried  for  45 
minutes  at  from  no  to  120°  C.  The  weight  obtained  is  multi- 
plied by  0.20326  to  convert  it  to  metallic  nickel  which  is  then 
calculated  to  percentage. 

The  percentage  of  20.326  corresponds  to  the  formula  of 
C8Hi4N4O4Ni.  Prettner  recommended  the  holding  of  the  solu- 
tion for  an  hour  before  filtering  off  the  scarlet  precipitate.  Those 
wishing  to  read  the  original  descriptions  of  the  method  should 
consult  Zeitschrift  fur  Angew.  Chemie,  1907,  Nr.  47,  S.  1844. 
Dr.  O.  Brunck.  Also  Chem.  Ztg.,  33,  1909,  p.  396. 

A  MODIFICATION  OF  BRUNCK'S  METHOD  BY  SOLUTION  OF 
THE  RED  PRECIPITATE  IN  NITRIC  ACID  AND  TITRATION 
OF  THE  SOLUTION  IN  THE  USUAL  WAY  WITH  KCN  AND 
SILVER  NITRATE. 

Proceed  as  for  nickel  as  in  Brunck's  method,  obtaining  the 
red  precipitate  which  is  washed  15  times  with  500  c.c.  of  water 
containing  10  c.c.  of  a  2  per  cent  solution  of  the  dimethyl.  The 
precipitate  is  dissolved  off  the  filter  with  25  c.c.  of  1.20  nitric 
acid,  allowing  the  solution  to  run  into  the  beaker  in  which  the 
precipitation  of  the  nickel  was  made.  Wash  the  filter  about 
30  times  with  water  containing  10  c.c.  of  1.20  nitric  acid  per 
500  c.c.  of  water,  or  until  the  wash  water  no  longer  gives  a  test 
for  nickel  with  the  dimethyl.  Add  15  c.c.  of  i  :  3  sulphuric  acid 


DETERMINATION  OF  NICKEL  IN  PRESENCE  OF  CHROMIUM     177 

to  the  nitric  acid  solution  of  the  red  precipitate;  boil  20  minutes; 
cool;  add  5  grams  of  citric  acid;  make  faintly  ammoniacal; 
add  10  drops  of  i  :  i  ammonia  and  finish  for  nickel  by  titration 
with  KCN  and  silver  nitrate.  By  this  method  the  U.  S.  nickel- 
chrome  standard  No.  32  (1.62  per  cent  Ni)  gave  1.63  per  cent 
nickel,  and  the  U.  S.  nickel  standard  No.  33  (3.33  per  cent  Ni) 
gave  3.36  per  cent  Ni. 

One  should  be  able  to  use  this  method  for  the  determination 
of  small  amounts  of  nickel  by  taking  large  weights  of  the  sample. 
Elements  like  manganese,  vanadium  and  chromium,  that  give 
very  dense  dark  citrates  when  in  the  "ous"  state,  could  be  anal- 
yzed for  small  per  cents  of  nickel  in  the  above  manner  by  separat- 
ing away  the  bulk  of  these  elements  from  the  nickel.  (See  the 
Determination  of  Small  Amounts  of  Nickel  in  the  Presence  of 
Large  Amounts  of  Cobalt,  page  314.)  The  idea  of  making  such 
a  modification  of  Brunck's  method  was  suggested  to  the  author 
by  Mr.  A.  G.  Greenameyer.  The  above  details  are  the  writer's. 

For  the  Determination  of  Nickel  by  Electrolysis,  see  page  316. 


CHAPTER  IX. 

PART  II. 
THE  ANALYSIS  OF  NICKEL-CHROMIUM  ALLOY. 

THE  widespread  application  of  true  nickel-chromium  and 
nickel-chromium-iron  alloys  to  resistance  heating  has  made 
further  work  for  the  analyst. 

The  author  has  analyzed  several  varieties  of  these  useful 
alloys  as  follows: 

NICKEL. 

Dissolve  0.5  gram  of  the  wire  in  a  No.  5  porcelain  dish  with  a 
mixture  of  20  c.c.  cone.  HC1  and  the  same  amount  of  cone. 
HNOs  and  evaporate  to  15  c.c.  Add  100  c.c.  of  cone.  HNOs  and 
evaporate  to  20  c.c.  Transfer  the  solution  to  a  600  c.c.  beaker; 
add  40  c.c.  of  i  :  3  H2SO4;  dilute  to  200  c.c.;  heat  to  boiling; 
add  permanganate  of  potassium  to  the  boiling  solution  until  an 
excess  of  brown  manganese  oxide  remains  without  perceptible 
change  after  a  half  hour  of  boiling;  cool;  filter  on  an  asbestos 
plug  or  through  an  alundum  thimble,  making  sure  that  none  of 
the  manganese  oxide  runs  through,  as  the  filtrate  must  be  per- 
fectly clear.  Cool;  add  i  :  i  ammonia  until  a  precipitate  starts 
to  form;  add  15  grams  of  citric  acid  made  slightly  alkaline  to 
litmus  paper  by  ammonia.  Add  10  drops  more  of  the  ammonia, 
if  necessary  to  render  the  solution  slightly  alkaline.  Titrate 
the  solution  with  the  concentrated  KCN  standard  given  on 
page  172.  To  standardize  the  cyanide  under  conditions  similar 
to  the  alloy,  put  the  following  mixtures  through  all  of  the  above 
operations  and  then  titrate  them  with  the  KCN:  Mixture  No. 
i,  i  gram  of  the  nickel-ammonium-sulphate,  and  200  mgs.  of 
potassium  dichromate;  mixture  No.  2,  2  grams  of  nickel-ammo- 

178 


THE  ANALYSIS  OF   NICKEL-CHROMIUM  ALLOY  179 

nium  sulphate  and  200  gms.  of  the  dichromate.  The  nickel- 
ammonium  sulphate  used  in  this  work  was  checked  by  elec- 
trolysis and  found  to  contain  14.6  per  cent  nickel,  hence  mixture 
No.  i  contained  0.146  X  i.oo  or  0.146  gram  of  nickel,  and  mix- 
ture No.  2  contained  0.146  X  2.00  or  0.292  gram  of  nickel. 

CHROMIUM. 

Dissolve  0.500  gram  of  the  finely  ground  sample  exactly  as 
given  for  nickel  and  proceed  with  the  analysis  as  for  nickel  and 
filter  off  the  excess  of  manganese  oxide  as  in  the  case  of  the  nickel. 
Cool  the  filtrate  if  the  titration  is  to  be  finished  forthwith;  omit 
the  neutralization  with  ammonia;  and  titrate,  after  adding 
40  c.c.  of  i  :  3  sulphuric  acid  and  diluting  further  to  250  c.c. 
with  water.  Titrate  with  the  same  strength  of  sulphate  and 
permanganate  standards  as  are  given  on  pages  33  and  34.  Do 
not  use  any  ferricyanide  indicator  as  the  nickel  would  be  pre- 
cipitated and  hide  the  end  point.  First  add  the  sulphate  stand- 
ard until  all  red  tints  are  gone  and  there  remains  only  the  chrome 
green;  then  add  an  apparent  excess  of  about  10  c.c.  Next 
titrate  with  the  equivalent  permanganate  standard  until  a  faint 
permanent  pink  flush  is  visible  through  the  green  of  the  chro- 
mium. The  amount  of  the  sulphate  used  less  the  number 
of  c.c.  of  the  permanganate  required  to  produce  the  pink  end 
point  is  multiplied  by  the  value  of  the  double  sulphate  in  chro- 
mium per  c.c.  The  result  equals  the  number  of  milligrams  of 
chromium  in  the  0.500  gram  of  sample.  The  standardization 
is  accomplished  by  putting  the  following  known  mixture  through 
all  of  the  foregoing  operations:  0.250  gram  of  plain  carbon  steel, 
o.ioo  gram  of  recrystallized  potassium  dichromate  and  2  grams 
of  nickel-ammonium  sulphate;  also  the  same  amounts  of  steel 
and  nickel  salt  with  0.200  gram  of  the  dichromate.  These 
mixtures  are  titrated  in  the  same  way  as  described  for  the  sample 
itself  and  the  value  of  the  sulphate  in  chromium  is  calculated 
in  the  usual  way.  The  value  of  the  dichromate  in  metallic 
chromium  is  taken  as  35.35  per  cent  Cr. 


l8o  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


MANGANESE. 

Dissolve  0.300  gram  of  the  wire  in  a  mixture  of  10  c.c.  of  cone, 
nitric  acid  and  5  c.c.  of  cone,  hydrochloric  acid.  Evaporate  to 
5.0  c.c.;  add  50  c.c.  of  cone,  nitric  acid  and  evaporate  to  10  c.c.; 
add  25  c.c.  more  of  the  nitric  acid  and  again  evaporate  to  10  c.c. 
Transfer  to  a  10  X  i  inch  tube  and  finish  as  in  chrome  steels, 
as  directed  on  page  15. 

CARBON. 

.  Twist  several  strands  of  the  wire  into  a  rope  and  take  millings 
therefrom  as  described  under  Milling  (see  page  221).  Then 
burn  with  red  lead  as  in  ferro-chromium. 

SULPHUR  AND  SILICON. 

The  sulphur  is  determined  as  in  the  gravimetric  method  for 
alloy  steels.  The  silicon  is  obtained  from  the  insoluble  matter 
filtered  out  before  precipitating  the  sulphur  with  barium  chloride. 

IRON  AND  ALUMINUM. 

Dissolve  i  gram  of  millings  in  a  mixture  of  20  c.c.  of  cone. 
HC1  and  20  c.c.  of  cone.  HNO3.  Heat  until  all  action  is  over; 
boil  down  to  20  c.c. ;  transfer  to  a  liter  boiling  flask;  dilute  to  300 
c.c.  and  peroxidize,  as  described  on  page  23,  getting  filtrates  A 
and  B,  and  if  B  has  a  distinct  yellow  color,  then  a  third  peroxi- 
dation  should  be  made,  obtaining  a  third  filtrate  and  washings 
C  that  are  free  from  an  appreciable  yellow  color,  showing  that 
all  of  the  chromium  has  been  separated  from  the  iron  present. 
The  aluminum  is  obtained  from  A,  B  and  C  as  in  ferro- vanadium 
that  is  by  adding  i  :  i  HC1  slowly  with  constant  stirring  until 
turmeric  paper  is  no  longer  immediately  turned  to  even  a  sug- 
gestion of  a  brownish  red  color  on  being  dipped  into  the  solution. 
The  operator  can  easily  tell  when  he  is  approaching  the  end  point 
by  the  sudden  increase  of  the  effervescence,  as  the  acid  is  added ; 


THE  ANALYSIS  OF  NICKEL-CHROMIUM  ALLOY  181 

also  if  aluminum  is  present  to  the  extent  of  even  one  per  cent 
the  solution  will  have  become  cloudy  and  if  several  per  cents 
are  present,  the  usual  white,  flocculent,  precipitate  of  aluminum 
hydroxide  will  have  formed.  Continue  to  add  the  acid  until 
the  turmeric  shows  no  more  immediate  change  of  color  than  if 
it  had  been  dipped  into  water.  Of  course  in  a  minute  or  two 
the  paper  will  take  on  a  faint  brownish  red.  At  this  stage  the 
solution  will  change  litmus  paper  at  once  to  a  distinct  blue.  A, 
B  and  C  can  be  combined  in  one  before  performing  the  precipi- 
tation of  the  aluminum,  or  if  the  volumes  are  too  great  they  can 
be  treated  separately  and  the  precipitates  combined  on  the  one 
filter.  The  alkaline  solution  is  brought  just  to  a  boil,  before 
adding  the  acid,  but  in  no  case  should  the  strongly  alkaline 
solution  be  heated  further,  as  by  so  doing  large  amounts  of 
glass  are  dissolved.  The  precipitate  of  aluminum  is  then  washed 
and  dissolved  off  the  filter,  reprecipitated  with  a  slight  excess 
of  ammonia  and  weighed  as  A12O3  plus  a  little  P2O5  and  Si02 
and  finished  from  that  point  on  as  given  on  page  19  and  on 
page  20. 

The  Iron:  All  of  the  iron  will  be  on  the  filter  from  filtrate  C 
except  a  slight  film  which  will  be  clinging  to  the  walls  of  the  boil- 
ing flask.  The  latter  is  cleaned  by  warming  in  the  flask  a  little 
i  :  i  HC1  and  the  iron  on  the  filter  is  dissolved  off  with  hot  acid 
of  the  same  kind.  The  iron  from  the  flask  and  the  filter  are 
combined  and  titrated  as  in  iron  ore  after  reduction  with  stan- 
nous  chloride.  To  standardize  the  dichromate  the  following 
known  mixture  was  put  through  all  of  the  foregoing  operations: 
250  mgs.  of  standard  iron  ore,  o.ioo  gram  of  potassium  dichro- 
mate and  2.00  gram  of  the  nickel-ammonium  sulphate.  Also 
for  a  check,  0.260  gram  of  the  iron  ore,  and  the  same  amounts 
of  the  other  two  salts  as  before.  The  Sibley  ore  No.  27  of  the 
U.  S.  Bureau  of  Standards  is  extremely  useful  as  a  known  source 
of  iron  to  add  to  all  such  standardizing  mixtures.  The  salts  of 
nickel  and  chromium  are  of  course  added  only  to  have  the  stand- 
ardizing mixtures  as  near  the  samples  as  possible. 


182 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


SOME  TYPES  OF  NICKEL-CHROMIUM  AND  NICKEL-CHROMIUM-IRON  ALLOYS. 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

Carbon  

0.  12 

0.35 

0.30 

o.  14 

Manganese 

o  82 

2   74 

I  .  ^O 

Trace 

Sulphur.  .  . 

O   OI2 

o  074 

0.027 

Nickel  ... 

76    Q3 

60.  3^ 

66.42 

83.91 

Chromium  

16.40 

IO.  12 

10.  17 

13.97 

Silicon 

O    23 

O   4.O 

Iron  

1.81 

2<J.II 

IO."23 

1.47 

Aluminum 

2  68 

O    ^3 

CHAPTER  IX. 

PART  III. 

THE  ANALYSIS  OF  NICKEL-COPPER  IRON  ALLOY 
(MONEL  METAL). 

SILICON  AND  COPPER. 

DISSOLVE  0.5  or  0.6  gram  of  the  drillings  or  millings  in  a 
No.  5  porcelain  dish  with  35  c.c.  of  1.20  nitric  acid.  In  the 
same  manner  dissolve  2  standardizing  mixtures  as  follows: 
(i)  o.ioo  gram  of  99.9  per  cent  metallic  copper  and  2.00  grams 
of  the  double  sulphate  of  nickel  and  ammonia.  (2)  0.200  gram 
of  the  copper  and  3.00  grams  of  the  double  sulphate.  Heat 
until  all  action  with  the  nitric  acid  has  ceased;  add  70  c.c.  of 
i  :  3  sulphuric  acid  and  evaporate  to  thick  white  fumes.  Add 
100  c.c.  of  water;  heat  until  all  is  in  solution  except  a  little  white 
insoluble  residue  of  flotant  silicic  acid  which  is  filtered  through 
a  double  1 1  c.c.  ashless  filter  and  washed  free  of  iron  with  water 
containing  10  per  cent  by  volume  of  i  :  3  sulphuric  acid.  Finish 
the  washing  with  water;  get  the  silicon  from  the  residue  on  the 
filter  as  in  steels,  page  286,  by  loss  of  weight  after  evaporation 
with  a  few  drops  of  cone,  sulphuric  acid  and  10  c.c.  of  hydro- 
fluoric acid.  Any  residue  of  oxides  remaining  after  this  evapo- 
ration and  ignition  is  dissolved  out  with  a  little  cone.  HC1  and 
the  solution  is  added  to  the  main  filtrate  from  the  silicon.  This 
filtrate  is  diluted  to  400  c.c.  with  water,  heated  nearly  to  boil- 
ing, and  hydrogen  sulphide  is  passed  through  it  until  the  cop- 
per separates  out  well.  Filter  the  sulphide  of  copper  through 
a  double  12  J  cm.  filter  and  wash  with  H2S  water  containing 
5  drops  of  i  :  3  sulphuric  acid  per  500  c.c.  of  water,  giving  not 
less  than  40  washings.  Dry  the  filter,  burn  it  off  at  a  low  red 
heat  in  a  porcelain  crucible,  and  dissolve  the  copper  oxide  in 

183 


184  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

20  c.c.  of  1.20  nitric  acid.  Transfer  the  solution  to  a  400  c.c. 
beaker;  add  1.5  grams  of  citric  acid;  make  neutral  with  a  sat- 
urated solution  of  sodium  carbonate  and  add  25  c.c.  excess  of 
the  carbonate.  Titrate  the  copper  by  the  cyanide  method  as 
described  on  pages  157  to  163.  For  the  indicator  use  a  20  per 
cent  KI  solution  (20  grams  of  the  KI  to  100  c.c.  of  water) ;  for 
the  cyanide  use  4.4868  grams  to  the  liter;  and  for  the  silver 
nitrate  dissolve  2.925  grams  in  water  and  dilute  to  i  liter.  It 
may  be  well  to  give  the  routine  of  the  titrations  here.  Add 
the  KCN  to  the  solutions  containing  the  various  amounts  of 
test  and  the  known  mixtures  until  all  blue  color  is  gone;  then 
wait  at  least  a  half  hour  before  proceeding  with  the  cyanide  and 
silver  titration.  Unless  this  pause  is  made  discordant  results 
will  be  obtained  owing  to  the  slowness  of  the  complete  reaction 
between  the  cyanide  added  to  discharge  the  blue,  and  the  copper. 
After  the  half  to  one  hour  interval,  add  2  c.c.  of  the  KI  indica- 
tor, and  then  the  silver  nitrate  until  a  slight  white  cloud  of  silver 
iodide  appears  that  is  permanent.  To  get  the  relation  between 
the  silver  and  the  cyanide  next  add  5  c.c.  of  the  KCN  standard 
and  again  add  the  silver  until  the  slight  cloud  again  appears. 

STANDARDIZATION  AND  CALCULATIONS. 

Mixture  No.  i  required  83.2  c.c.  of  the  KCN  to  discharge  the 
blue  color,  and  after  waiting  for  at  least  a  half  hour  it  required 
6.5  c.c.  of  the  AgNOs  standard  to  produce  a  slight  cloud  of  silver 
iodide  in  the  solution ;  further,  on  adding  an  excess  of  the  KCN  of 
5  c.c.  it  required  4.3  c.c.  of  the  AgN03  to  again  produce  a  slight 
permanent  cloud  in  No.  i.  By  this  last  titration,  therefore, 
4.3  c.c.  of  the  " silver"  equal  5.0  c.c.  of  the  cyanide.  Since 
6.5  c.c.  of  the  silver  solution  were  needed  to  produce  the  first 
slight  cloud  after  the  30  minute  delay,  then  6.5  X  5  divided  by 
4.3  or  7.5  c.c.  must  be  deducted  from  the  83.2  c.c.  required  to 
discharge  the  first  blue  in  order  to  obtain  the  actual  amount  of 
the  KCN  standard  that  was  used  by  the  copper  taken.  This 
gives  75.7  c.c.  of  the  KCN  equal  to  o.ioo  X  99.9  of  metallic 
copper  or  0.0999  gram,  or  i  c.c.  of  the  KCN  equals  0.00132 


THE  ANALYSIS  OF  NICKEL-COPPER   IRON  ALLOY         185 

gram  of  copper.  In  the  same  way  from  mixture  No.  2  it  was 
found  that  149.8  c.c.  of  the  KCN  equal  0.1998  gram  of  copper, 
or  i  c.c.  of  the  KCN  equals  0.001333  gram  of  copper.  The 
average  of  the  two  standardizations  was  0.00133.  In  the  same 
manner  0.5  and  0.6  gram  of  the  monel  gave  26.6  and  26.9  per 
cent  copper. 

NICKEL  ix  MONEL. 

The  nitrates  from  the  H2S  precipitation  of  the  copper  are 
evaporated  to  fumes  with  100  c.c.  of  i  :  3  H^SC^;  cool;  add  50 
c.c.  of  water;  and  then  10  c.c.  of  cone.  HNOs;  heat  to  destroy 
any  remaining  hydrogen  sulphide;  filter  if  not  clear,  and  titrate 
with  cyanide  and  silver.  For  the  cyanide  standard  dissolve 
44.868  grams  of  KCN  in  water  and  dilute  to  2  liters,  and  for 
the  silver  nitrate  and  the  potassium  iodide  use  the  same  strength 
as  given  for  the  copper.  In  making  the  titration  add  2  c.c.  of 
the  KI  and  then  the  AgNOs  until  a  distinct  white  cloud  of  the 
silver  iodide  is  formed;  then  add  the  KCN  until  the  cloud 
just  disappears;  then  add  10  c.c.  excess  of  the  KCN  and  just 
bring  back  the  white  cloud  to  get  the  relation  between  the  silver 
nitrate  and  the  KCN.  As  No.  i  (see  copper)  contained  2  grams 
of  the  nickel  ammonium  sulphate,  there  were  present,  theo- 
retically, 0.1486  X  2.00,  or  0.2972  gram  of  nickel.  By  the  ex- 
cess titration  it  was  found  that  i  c.c.  of  the  AgNO3  equals  0.21 
c.c.  of  the  KCN.  The  first  cloud  produced  by  the  addition  of 
the  2  c.c.  of  KI  did  not  disappear  until  61.0  c.c.  of  the  KCN  had 
been  added.  In  this  standardization  2.4  c.c.  of  the  AgNOa 
were  actually  added  to  produce  the  cloud  with  the  KI;  and  by 
the  titration  of  the  10  c.c.  of  excess  KCN,  47.6  c.c.  of  the  AgNO3 
were  required  to  again  reproduce  the  cloud;  therefore,  61.0  c.c. 
less  2.4  X  10  divided  by  47.6,  or  less  0.504  c.c.,  equal  60.5  c.c. 
which  equal  0.2972  gram  of  nickel,  or  i  c.c.  of  the  KCN  equals 
0.00491  gram  of  nickel.  In  the  same  way  mixture  No.  2  gave 
i  c.c.  of  the  KCN  standard  equals  0.00493  gram  of  nickel.  From 
the  0.5  and  0.6  gram  of  the  monel,  68.82  and  68.63  per  cent 
nickel  were  found. 


l86  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

IRON. 

Dissolve  i  or  i|  gram  of  sample  in  25  c.c.  of  1.20  c.c.  nitric 
acid  in  an  800  c.c.  beaker  and  dilute  to  500  c.c.  Precipitate 
the  iron  with  a  considerable  excess  of  ammonia  and  let  the  solu- 
tion stand  until  the  iron  is  well  separated.  Filter  it  off;  wash 
the  precipitate  with  i  :  20  ammonia  until  the  washings  are  no 
longer  colored  blue;  then  redissolve  the  iron  with  40  c.c.  of  i  :  i 
HC1;  wash  the  filter  free  of  iron  with  i  :  20  HC1  and  precipitate 
the  filtrate  and  washings  as  before  with  an  excess  of  ammonia; 
filter  off  the  iron  hydroxide;  wash  it  as  above;  dissolve  it  as 
before;  dilute  the  filtrate  and  washings  from  this  HC1  solution 
to  300  c.c.;  heat  to  boiling;  add  stannous  chloride  until  the 
iron  is  decolorized  and  three  or  four  drops  in  excess;  cool;  add 
35  c.c.  of  the  mercuric  chloride  solution;  stir  and  titrate  at  once 
with  a  dichromate  of  potassium  made  by  dissolving  1.225  grams 
of  this  salt  in  water  and  diluting  it  to  i  liter.  Add  the  dichro- 
mate standard  until  the  solution  being  titrated  no  longer  gives 
a  blue  spot  test  with  potassium  ferricyanide  when  two  drops  of 
it  are  mixed  with  the  same  amount  of  the  ferricyanide  indicator 
on  the  usual  porcelain  plate.  To  standardize  the  dichromate 
put  enough  of  the  iron  ore  furnished  by  the  Bureau  of  Standards 
or  of  some  other  equally  reliable  iron  standard  through  all  of 
the  foregoing  manipulations  as  though  Ni  and  Cu  were  present, 
and  titrate  with  the  dichromate  standard.  In  one  such  analy- 
sis, enough  iron  ore  standard  was  taken  to  equal  30  and  60  mgs. 
of  metallic  iron  in  solution.  This  gave  i  c.c.  of  the  dichromate 
equals  0.00141  gram  of  iron. 

The  mercuric  chloride  solution  is  made  by  dissolving  50  grams 
of  the  salt  in  1000  c.c.  of  water. 

The  stannous  chloride  is  made  by  dissolving  10  grams  of  stan- 
nous chloride  or  an  equivalent  amount  of  pure  tin  in  100  c.c. 
i  :  i  HC1. 

The  ferricyanide  is  prepared  by  dissolving  0.50  gram  of  this 
salt  in  100  c.c.  of  water  at  the  time  it  is  to  be  used  to  get  the 
sharpest  end  point. 


THE  ANALYSIS  OF  NICKEL-COPPER  IRON  ALLOY 


i87 


CARBON,  MANGANESE,  SULPHUR  AND  PHOSPHORUS. 

The  sulphur  is  found  by  the  gravimetric  method  as  in  plain 
steels,  as  given  on  page  274,  the  carbon  by  direct  combustion 
in  oxygen,  the  manganese  by  the  volumetric  method  given  on 
page  276  and  the  phosphorus  as  given  on  pages  257  to  264. 


SOME  ANALYSES  OF  MONEL  METAL. 


No.  i. 

No.  2. 

No.  3. 

Carbon  

O.I1? 

O.  IO 

o.  30 

Manganese 

Trace 

327 

Phosphorus. 

O    O2O 

O  OI7 

O   O4.? 

Sulphur  

o  04.3 

O   O2O 

o  063 

Silicon  

o  236 

O    IQO 

O   67 

Iron  

2    QO 

3    08 

Nickel 

68  82 

69  1  8 

66  78 

Cooper 

26  o^ 

27    2d. 

24  86 

CHAPTER  X. 

PART  I. 
FERRO-MANGANESE. 

GRAVIMETRIC  METHOD. 

DISSOLVE  one  gram  of  sample  in  50  c.c.  of  1.20  nitric  acid  in  a 
No.  4  porcelain  dish.  Remove  the  watch  glass.  Evaporate 
to  dryness.  Ignite  to  low  red  heat  to  destroy  the  carbon.  Re- 
place the  cover.  Dissolve  in  40  c.c.  cone,  hydrochloric  acid. 
Heat  until  fumes  of  chlorine  have  disappeared.  Filter  into  an 
800  c.c.  beaker.  Wash  the  residue  on  the  filter  with  i  :  10 
hydrochloric  acid  until  it  is  free  from  iron  test.  Wash  it  further 
with  water  until  it  is  free  from  chlorine  test.  Ignite  the  residue 
in  a  weighed  crucible  and  finish  for  silicon  as  in  steels. 

Dilute  the  filtrate  and  washings  to  300  c.c.  Add  dilute  am- 
monia until  one  drop  produces  a  precipitate  that  fails  to  dissolve 
with  persistent  stirring.  Now  add  one  drop,  only,  of  i  :  i  hy- 
drochloric acid.  Also  pour  into  the  solution  i  .5  c.c.  of  ammonium 
acetate  for  every  100  mgs.  of  metallic  iron  supposed  to  be  pres- 
ent. (The  ammonium  acetate  solution  is  prepared  by  dissolving 
50  grams  of  the  salt  in  50  c.c.  of  water.  Add  dilute  ammonia 
to  this  solution  a  drop  at  a  time  until  it  smells  very  faintly  of 
ammonia.*  Add  water  until  the  total  volume  of  the  acetate  solu- 
tion is  100  c.c.)  Heat  to  boiling.  Boil  one  minute.  Permit  the 
precipitate  to  settle  a  few  moments.  Stir  in  some  paper  pulp. 
Filter  hot.  Wash  fifteen  times  with  hot  water  containing  2  c.c. 
of  ammonium  acetate  to  100  c.c.  of  water. 

Redissolve  the  precipitate  with  10  c.c.  of  hot  i  :  i  hydro- 
chloric acid.  Wash  the  filter  free  from  iron  test.  Dilute  the 
filtrate  and  washings  to  200  c.c.  and  precipitate  it  again  as  before. 

*  Or  reacts  slightly  blue  with  red  litmus  paper. 
188 


FERRO-MANGANESE  189 

Wash  the  precipitate.  Combine  this  nitrate  and  washings  with 
the  original  filtrate  and  washings.  Evaporate  all  (after  adding 
to  the  combined  filtrates  5  c.c.  of  i  :  i  hydrochloric  acid)  to 
200  c.c.  Filter  if  necessary.  Add  25  c.c.  of  ammonium  acetate 
solution.  Heat  to  boiling  in  a  platinum  or  porcelain  dish.  Add* 
to  the  boiling  solution  75  c.c.  of  a  saturated  solution  of  micro- 
cosmic  salt,  stirring  continuously.  Add  a  slight  excess  of  ammo- 
nia, and  continue  to  heat  the  precipitate  and  supernatant  fluid 
with  frequent  stirring  until  the  pink  manganese  phosphate 
changes  from  a  flocculent  slimy  precipitate  to  a  pink  crystalline 
heavy  one  that  settles  rapidly  to  the  bottom  of  the  vessel. 
When  cold,  filter  out  the  manganese  phosphate  and  wash  it 
with  cold  water  until  no  milkiness  is  obtained  from  the  washings 
on  being  acidulated  with  a  drop  or  two  of  nitric  acid  and  tested 
with  a  drop  of  silver  nitrate  solution. 

Add  10  c.c.  more  of  the  precipitant  to  the  filtrate  and  wash- 
ings. If  a  precipitate  forms  after  several  hours,  collect  it; 
wash  it  as  in  the  main  precipitate.  Dry  the  two  filters  con- 
taining the  phosphate.  Remove  the  latter  to  a  large  watch 
glass.  Cover  it.  Burn  its  filter  in  a  weighed  platinum  crucible 
at  a  low  red  heat  until  all  black  is  gone.  Now  add  the  small 
residue,  if  any,  obtained  from  the  filtrate  and  washings  tested 
with  10  c.c.  of  the  phosphate  of  sodium  and  ammonium.  When 
this  residue  has  been  burned  white  at  the  lowest  possible  heat, 
add  the  main  phosphate  precipitate  and  ignite  it  very  slowly 
to  prevent  loss  by  dusting  due  to  liberation  of  ammonia.  Then 
raise  the  heat  to  redness  until  all  carbon  is  gone.  Weigh  the 
precipitate  as  Mn2P207.  Dissolve  the  same  in  i  :  i  hydrochloric 
acid,  and  if  the  solution  contains  any  insoluble  matter  such  as 
silicic  acid,  filter  it  out.  Wash  it.  Ignite  and  weigh  it.  De- 
duct the  weight  from  the  weight  of  the  Mn2P2O7,  multiply  the 
remainder  by  38.69  and  divide  by  the  weight  taken  for  analysis 
to  obtain  the  per  cent  of  manganese. 

*  Add  only  enough  of  the  i  :  i  ammonia,  at  first,  to  produce  a  slight  milki- 
ness. Stir  the  boiling  solution  until  this  milky  precipitate  becomes  heavy  and 
crystalline.  Then  add  the  balance  of  the  ammonia,  slowly,  and  with  constant 
stirring  to  the  boiling  solution,  making  sure  that  an  excess  of  ammonia  is  used. 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

If  the  quick  nickel  test  (see  Chapter  IX,  page  164)  shows  that 
considerable  nickel  or  copper  is  present,  these  elements  should 
be  removed  by  hydrogen  sulphide  before  making  the  phosphate 
precipitations.  This  can  be  done  as  follows:  Make  the  nitrate 
from  the  iron  hydroxide  slightly  acid  with  acetic  acid  and  pass 
H2S  through  it  until  the  sulphides  collect  and  settle  out  well; 
filter ;  wash  with  H2S  water ;  concentrate  the  filtrates  and  wash- 
ings until  crystallization  begins.  Dilute  with  enough  cold 
water  to  dissolve  the  crystals;  filter  again;  wash  with  water, 
alone,  and  then  proceed  with  the  phosphate  precipitation  of 
the  filtrate  as  in  the  first  gravimetric  method. 

VOLUMETRIC  METHOD  FOR  MANGANESE. 

Proceed  by  a  bisulphate  fusion  as  .given  for  high  manganese 
in  insoluble  ferro-titanium.  Fuse  0.3  gram  for  80  per  cent 
ferro;  0.5  gram  for  50  per  cent  and  i  gram  for  lower  percentages 
of  manganese. 

For  standardizing  the  permanganate  solution  it  is  better  to 
weigh  0.3  gram  of  a  ferro-manganese  whose  manganese  content 
has  been  carefully  determined  by  the  gravimetric  process.  Put 
it  through  the  entire  volumetric  operation,  and,  in  this  way, 
fix  the  value  of  the  permanganate  standard  in  milligrams  of 
manganese,  rather  than  by  the  standardization  given  on  page  49. 

PHOSPHORUS. 

The  precipitate  of  ferric  acetate  contains  all  of  the  phos- 
phorus. It  can  be  dissolved  off  the  filter  and  evaporated  to 
moist  dryness  on  the  water  lath.  Dissolve  the  residue  in  50 
c.c.  of  cone,  nitric  acid.  Evaporate  to  about  5  c.c.  Rinse  into 
a  5-ounce  beaker.  Boil  with  permanganate  and  finish  the 
phosphorus  as  in  steel. 

The  phosphorus  may  be  determined  on  a  separate  portion  by 
dissolving  i  gram  in  nitric  acid.  Evaporate  to  dryness.  Ignite 
to  a  dull  red.  Dissolve  in  HC1.  Convert  into  nitrate.  Filter 
and  finish  as  in  steels. 


FERRO-M  ANGANESE  191 

SULPHUR. 
1  Sulphur  is  obtained  as  in  steels  by  the  gravimetric  method. 

FERRO-SILICQN,  SILICON  SPIEGEL  AND  METALLIC  SILICON. 

Silicon  and  Manganese.  These  high  silicon  materials  should 
be  fused  with  sodium  carbonate  and  potassium  nitrate.  Fuse  * 
i  gram  with  20  grams  of  sodium  carbonate  intimately  mixed 
with  4  grams  of  finely  ground  potassium  nitrate.  Dissolve 
the  melt  in  water  in  a  platinum  dish.  Transfer  the  green  fluid 
and  residue  to  a  large  casserole.  Cover  with  a  watch  glass. 
Add  an  excess  of  concentrated  hydrochloric  acid,  keeping  the 
vessel  covered.  Clean  the  crucible  with  a  few  c.c.  of  the  same 
acid.  Add  the  cleanings  to  the  acidulated  fusion.  Heat  until 
all  spraying  ceases.  Wash  off  the  cover,  allowing  the  fluid  to 
flow  into  the  casserole.  Evaporate  to  dryness  on  a  graphite  or 
sand  bath.  Add  10  c.c.  cone,  hydrochloric  acid.  Warm,  add 
100  c.c.  of  water  and  heat  for  a  half  hour,  or  until  all  salt  is 
dissolved.  Filter.  Wash  the  silicious  residue  free  of  chloride 
test.  Evaporate  filtrate  and  washings  again  to  dryness.  Dis- 
solve, filter  and  wash  as  before.  Dry  the  two  residues  obtained 
from  the  first  and  second  nitrations.  Roast  off  the  paper  from 
them  at  the  lowest  possible  heat  to  prevent  loss  of  silica.  Then 
gradually  raise  the  heat  and  blast  the  residues  in  a  weighed  plat- 
inum crucible  until  the  weight  of  the  ash  is  constant.  Moisten 
the  silica,  which  should  be  white,  with  a  few  drops  of  sulphuric 
acid.  Fill  the  crucible  nearly  full  of  hydrofluoric  acid.  Add 
the  latter  cautiously,  at  first.  Evaporate  and  finish  for  silicon 
as  in  steels.  It  is  safer  to  evaporate  a  second  time  with  hydro- 
fluoric and  sulphuric  acids,  using  about  one-third  as  much 
hydrofluoric  acid  as  was  used  in  the  first  evaporation,  to  make 
sure  that  all  silicon  has  been  volatilized. 

*  Fuse  0.5  gram  in  an  iron  crucible  with  a  mixture  of  4  grams  of  sodium  per- 
oxide and  8  grams  of  sodium  carbonate,  if  silicon,  only,  is  required.  Run  blanks. 


192  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Manganese  and  Iron.  The  filtrate  from  the  second  evapora- 
tion to  dryness  should  now  be  divided  into  two  equal  portions.* 

FIRST  PORTION. 

Phosphorus  and  Sulphur.  Precipitate  with  a  slight  excess 
of  ammonia.  Wash  the  precipitate  with  water.  Dissolve  it 
off  the  filter  with  hot  concentrated  hydrochloric  acid,  using  a 
little  sulphurous  acid  if  necessary.  Convert  this  solution  of  the 
iron  into  nitrate;  boil  with  a  little  permanganate  and  finish 
for  phosphorus  as  in  steels,  calculating  the  percentage  on  a 
half  gram  basis. 

Sulphur.  The  filtrate  from  the  ammonia  precipitation  is 
made  slightly  acid  with  hydrochloric  acid.  The  sulphur  is  pre- 
cipitated with  barium  chloride  and  finished  as  in  steels.  De- 
duct a  blank  obtained  on  all  of  the  fluxes  and  acids.  If  it  is 
desired  to  use  a  larger  amount  of  sample  for  sulphur,  it  can 
be  determined  alone  on  a  one  gram  quantity  without  dividing 
into  two  portions. 

SECOND  PORTION. 

Manganese  and  Iron;  Manganese.  This  portion  is  evap- 
orated to  fumes  with  sulphuric  acid.  The  iron  is  precipitated 
with  ZnO  and  filtered  out.  The  filtrate  is  finished  for  man- 
ganese as  given  for  high  manganese  in  insoluble  ferro-titanium 
of  high  manganese  content.  (Page  52.) 

The  Iron.  The  iron  and  zinc  oxide  residues  on  the  filter  are 
dissolved  off  with  hot  sulphuric  acid  and  reduced  with  zinc  and 
titrated  for  iron  in  the  same  manner  as  given  for  iron  in  ferro- 
vanadium.  (See  page  29.  See  also  page  368.) 

fThe  Carbon.  The  carbon  can  be  obtained  by  combustion 
of  0.5  gram  of  the  ferro-manganese,  etc.,  with  4  grams  of  red 
lead;  or  litharge  is  equally  good  as  a  substitute  for  the  red  lead. 

*  The  residue  in  the  crucible  after  the  volatilization  of  the  silica  with  HF1 
is  quite  likely  to  contain  a  little  iron  and  manganese.  It  should  be  dissolved  by 
warming  with  a  little  i  :  i  HCl  and  added  to  the  filtrate  from  the  second  evap- 
oration to  dryness  before  the  same  is  divided  into  two  portions. 

t  The  carbon  of  ferro-silicon  should  be  determined  on  a  small  quantity  of  the 
material  on  account  of  the  great  heat  generated.  Do  not  burn  more  than  0.500 
gram  at  a  time.  Use  4  grams  of  the  red  lead. 


CHAPTER  X. 

PART  II. 

RAPID  VOLUMETRIC  METHOD  FOR  MANGANESE  IN  THE 
PRESENCE  OF  IRON,  CALCIUM  AND  MAGNESIUM. 

THE  usefulness  of  potassium  ferricyanide  in  the  determination 
of  copper  and  nickel  in  steel,  pig  iron  and  ferro-vanadium  led 
the  author  to  investigate  its  quantitative  application  to  the 
analysis  of  manganese.  After  considerable  experimentation 
the  following  method  was  developed  for  manganese  in  ferro- 
manganese,  and  manganese  steel.  It  is  assumed  that  inter- 
fering metals,  like  copper,  nickel  and  zinc,  are  not  present  in 
appreciable  amounts:  Pulverize  a  pound  or  two  of  80  per  cent 
ferro-manganese,  and  accurately  determine  its  manganese  con- 
tent by  the  gravimetric  methods  as  given.  Use  a  ferro  that 
tests  practically  free  from  nickel  by  the  method  described  under 
Nickel  in  Steel,  etc.,  pages  164-176. 

Method.  Weigh  0.5  and  0.6  gram  of  the  standard  ferro  into 
5-ounce  beakers,  and  also  the  same  quantities  of  the  sample  to 
be  tested.  Dissolve  these  portions  with  50  c.c.  of  1.20  nitric  acid, 
keeping  the  beakers  covered  with  watch  glasses  during  the  slow 
boiling.  When  the  action  is  over  and  all  of  the  samples  are  in 
solution,  except  perhaps  a  few  brown  particles  of  carbon  (in  the 
case  of  high-carbon  ferros),  remove  the  beakers  from  the  fire. 
This  is  done  before  the  solutions  have  concentrated  to  any 
extent.  Cool  and  rinse  one  of  the  standards  into  a  liter  beaker. 
Add  an  additional  50  c.c.  of  1.20  nitric  acid  to  insure  the  pres- 
ence of  considerable  salt.  Dilute  to  500  c.c.  with  water.  Add 
i  :  i  ammonia,  little  by  little,  with  constant  stirring,  until  the 
iron  just  begins  to  precipitate.  Continue  to  add  the  ammonia, 
drop  by  drop,  until  the  iron  separates  completely  and  settles. 
The  solution  should  now  smell  but  VERY  FAINTLY  of  ammonia, 


IQ4  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

and  have  the  characteristic  rather  sickening  sweetish  smell  of 
a  nearly  neutral  ammonia  solution. 

Avoid  Any  Large  Excess  of  Ammonia.  Mix  with  the  hydrox- 
ide a  thick  cream  of  precipitated  barium  carbonate,  free  from 
copper.  About  10  c.c.  of  this  mixture  of  carbonate  and  water 
are  sufficient.  After  stirring  the  carbonate  through  the  iron 
hydroxide  there  should  remain  enough  of  the  carbonate  to  form 
a  white  spot  about  the  size  of  a  dollar  on  the  bottom  of  the 
beaker.  The  barium  salt  insures  a  constant  SLIGHT  excess  of 
free  ammonia,  which  is  necessary  to  produce  a  rapidly  settling 
precipitate  on  the  addition  of  the  ferricyanide  standard.  Add 
the  latter  slowly  from  100  c.c.  burette,  at  the  rate  of  100  c.c. 
every  four  minutes,  stirring  the  contents  of  the  liter  beaker 
vigorously.  A  stirring  rod  is  used  with  its  lower  end  covered 
with  a  small  rubber  cap  to  prevent  the  cracking  of  the  beaker. 
For  high  per  cent  ferros  use  a  ferricyanide  solution  containing 
15  grams  of  this  salt  to  2  liters  of  water. 

The  ferricyanide,  at  first,  produces  a  nearly  white  precipitate 
with  the  manganese,  in  the  slightly  alkaline  solution.  This 
compound  quickly  changes  to  a  brown  color.  As  the  end  of 
the  reaction  between  the  standard  solution  and  the  manganese 
is  neared,  this  flocculent  precipitate  collects  and  settles  to  the 
bottom  of  the  beaker  in  i  or  2  minutes.  The  substance  turns 
bright  blue  on  being  mixed  with  a  little  ferrous  iron  in  acid, 
acting  in  this  respect  like  potassium  ferricyanide.  When  all  but 
10  or  15  c.c.  of  the  probable  amount  of  standard  solution  needed 
have  been  dropped  slowly  into  the  beaker,  accompanied  with 
continuous  stirring,  stop  adding  the  ferricyanide  and  stir  vigor- 
ously for  60  seconds  more.  Lay  the  stirring  rod  across  the 
mouth  of  the  beaker  with  the  rubber  end  resting  on  the  lip 
of  the  same  and  projecting  about  an  inch  beyond.  Place  the 
index  finger  firmly  over  the  other  part  of  the  rod  and  grasp  the 
beaker  with  the  rest  of  this  hand.  Now  pour  exactly  20  drops 
of  the  fluid  through  a  7  cm.  filter  into  a  152.4  by  16  mm.  test 
tube.  If  the  filters  are  thin,  use  them  double,  for,  if  any  of  the 
brown  precipitate  were  to  run  through,  it  would  give  an  intense 


VOLUMETRIC  METHOD   FOR  MANGANESE  IN  IRON,   ETC.     195 

blue  with  the  indicator  (ferrous  chloride)  and  a  false  end  point. 
When  making  these  tests  for  end  point,  one  should  have,  at 
hand,  about  two  dozen  test  tubes.  Do  not  use  the  same  test 
tube  for  the  next  trial,  as  these  tubes  gradually  get  a  coating  on 
the  inner  surface  that  gives  a  faint  blue  color  with  ferrous  salts. 
Clean  the  tubes  that  have  been  used  for  end  point  tests,  first 
with  water;  then- with  concentrated  ammonia  to  remove  the 
coating;  then  with  water  to  remove  the  ammonia;  next  with 
i  :  i  hydrochloric  acid;  and,  finally,  with  distilled  water.  The 
tubes  are  then  ready  for  further  end  point  tests.  To  the  clear 
filtrate,  in  the  clean  test  tube,  add  a  few  drops  of  ferrous  chloride. 
Compare  the  blue  color,  if  any  is  obtained,  with  that  of  a  similar 
tint  obtained  as  follows:  In  800  c.c.  of  distilled  water  containing 
three  drops  of  i  :  i  ammonia,  drop  \  c.c.  of  the  standard  ferri- 
cyanide  solution.  Mix  thoroughly  with  a  stirring  rod.  Pour 
just  2  c.c.  of  this  mixture  into  a  152.4  by  16  mm.  test  tube,  and 
add  to  it  a  few  drops  of  the  ferrous  chloride.  This  gives  a  blue 
color  of  a  DEFINITE  depth  of  color.  If  the  test  gives  a  blue  color 
that  is  lighter  than  the  standard  blue,  then  add  another  c.c.  of 
the  ferricyanide  to  the  solution  being  titrated,  and  stir  it  swiftly 
for  one  minute.  Have  a  watch  at  hand  and  stir  exactly  60  sec- 
onds. If  a  blue  color  is  now  gotten  that  is  deeper  in  shade  than 
that  in  the  standard  tube,  then  stir  the  solution  for  60  seconds 
more  and  again  filter  from  it  just  20  drops  of  solution.  If  this 
filtrate  gives  a  blue  with  the  ferrous  chloride  that  is  darker 
than  the  standard  blue,  the  titration  is  considered  complete, 
and  \  c.c.  is  deducted  from  the  total  amount  of  ferricyanide 
standard  required.  If  the  filtrate  from  the  second  testing  gives 
a  lighter  blue,  then  i  c.c.  more  of  the  standard  ferricyanide 
is  added  to  the  solution  being  tested,  and,  after  one  minute's 
stirring,  20  drops  are  again  filtered  and  tested  with  ferrous 
chloride.  The  blue  of  the  test  should  now  be  quite  a  bit  darker 
than  the  standard  blue.  Again  the  solution,  being  tested,  is 
stirred  60  seconds  and  20  drops  filtered  and  treated  with  a  few 
drops  of  ferrous  chloride,  which  will  most  likely  give  a  blue 
either  matching  the  standard  blue  or  a  little  darker.  If  the 


196  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

colors  match,  make  no  deduction  from  the  total  cyanide 
used. 

The  object  of  the  two  stirrings  and  testings,  after  each  addi- 
tion of  i  c.c.  of  the  standard,  as  the  end  point  is  near,  is  to  make 
certain  that  the  ferricyanide  is  not  being  still  slowly  combined 
with  any  manganese  salt  that  may  be  occluded  by  the  volu- 
minous precipitate.  This  would  be  shown  by  the  blue  test,  taken 
after  further  stirring,  being  fainter  in  color  than  the  test  taken 
at  the  preceding  stirring. 

As  the  blue  tests  seem  to  get  darker  on  standing,  the  standard 
blue  must  be  made  fresh  each  time  that  a  test  is  taken  from  the 
solution  being  assayed.  That  is,  2  c.c.  of  the  800  c.c.  of  stock 
are  also  taken  and  made  blue  with  a  few  drops  of  ferrous  chloride 
at  the  same  time  with  each  20  drop  test. 

Suppose  the  standard  ferro-manganese  powder  contains  79.8 
per  cent  of  manganese;  that  216.3  c-c-  were  required  of  the 
standard  to  precipitate  all  of  it  and  give  the  first  and  second 
blue  tests:  Then,  if  0.600  gram  of  the  standard  ferro  were  taken, 
0.600  X  0.798  -s-  215.8  =  0.002218,  or  i  c.c.  of  the  standard 
ferricyanide  solution  equals  0.002218  gram  of  manganese  under 
the  conditions  as  given.  This  factor  should  be  fixed  by  the  oper- 
ator. 

One  of  the  weights  of  the  sample  submitted  should  now  be 
titrated  exactly  as  described  for  the  standard.  If  a  result 
within  10  per  cent  of  the  standard  is  obtained,  then  that  result 
is  sufficiently  accurate  for  all  technical  purposes;  i.e.,  correct 
within  less  than  one-half  of  i  per  cent  in  a  possible  80  per  cent. 
It  is  advisable  to  make  the  analysis  in  duplicate,  and  also  the 
standardizations,  using  0.5  and  0.6  gram  in  the  case  of  80  per 
cent  ferro-manganese  and  correspondingly  larger  amounts  of 
lower  grade  ferros.  Should  a  very  much  lower  percentage 
be  found,  for  instance  42  per  cent,  then  this  finding  is  most 
likely  i  to  2  per  cent  too  low.  To  arrive  at  the  exact  manganese, 
repeat  the  analysis  so  that  the  standard  and  the  test  contain  as 
closely  as  possible  the  same  amounts  of  iron  and  manganese  in 
solution.  For  the  example  cited,  weigh  for  standardizing  pur- 


VOLUMETRIC  METHOD   FOR  MANGANESE   IN  IRON,  ETC.     197 

poses  0.550  gram  of  the  standard  ferro,  and  in  the  same  beaker 
also  450  -mgs.  of  an  iron,  or  iron  wire  containing  0.05  per 
cent,  or  less,  of  manganese.  Of  the  sample  to  be  determined 
weigh  i  gram.  This  gives  a  standard  mixture  and  a  test  con- 
taining very  nearly  the  same  amounts  of  iron  and  manganese 
in  solution.  Proceed  with  the  second  analysis  as  outlined  in 
the  trial,  obtaining  a  higher  factor  for  the  standard  solution 
(i  c.c.  =  about  0.002318  gram  Mn).* 

As  the  chemist  usually  knows,  beforehand,  within  a  few  per 
cent,  the  percentage  of  manganese  in  the  test,  these  trial  anal- 
yses are,  as  a  rule,  not  necessary.  He  needs  only  to  observe 
the  precaution  of  taking  weights  of  the  standard  and  of  the 
tests  so  as  to  have,  in  each,  approximately  the  same  amounts 
of  iron  and  manganese.  For  further  illustration,  suppose  it  is 
desired  to  assay  a  steel  of  about  13  per  cent  manganese.  Allow- 
ing for  about  i  per  cent  of  other  elements  besides  iron,  i  gram 
of  such  a  steel  would  contain  close  to  130  mgs.  of  manga- 
nese and  860  mgs.  of  iron.  To  fix  the  manganese  factor  value 
of  the  ferricyanide  for  the  titration  of  i  gram  of  this  steel, 
weigh  0.130  -f-  0.8,  or  0.1625  gram,  of  the  80  per  cent  standard 
ferro-manganese  and  0.84  gram  of  a  low  manganese  iron  into 
the  same  beaker.  Titrate  such  steels  exactly  as  the  ferro-man- 
ganese except  that  a  ferricyanide  standard  of  one-half  the  strength 
of  that  given  for  ferro-manganese,  or  3.75  grams  to  the  liter,  is 
advisable.  And  so  on  for  steels  ranging  lower  in  manganese 
content,  preparing  standardizing  mixtures  from  a  standard  steel 
containing  from  12  to  15  per  cent  of  manganese. 

Ferricyanide  standard  solutions  should  be  kept  in  the  dark 
and  standardized  each  day  that  they  are  in  use.  Clean  the 
beaker  and  rod,  after  each  titration,  with  i  :  i  hydrochloric 
acid,  rinsing  out  the  acid  with  water  before  making  the  next 
titration. 

Instead  of  standardizing  with  ferro-manganese,  one  can  use 
c.p.  permanganate  of  potassium  and  iron  wire,  making  mixtures  to 
almost  exactly  imitate  the  probable  manganese  and  iron  content 

*  Read  page  201. 


198  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

of  the  test.  For  example,  suppose  it  is  desired  to  analyze, 
at  the  same  time,  a  ferro  about  90  per  cent  Mn,  one  about  43 
per  cent  and  one  about  80  per  cent  Mn.  For  standard  take 
1.3  grams  of  c.p.  crystals  of  potassium  permanganate,  and  weigh 
also  into  the  same  beaker  0.500  gram  of  low  manganese  muck 
iron  and  2.5  grams  of  oxalic  acid.  Cover  the  beaker  and  add  a 
few  drops  of  water.  After  the  first  violent  action  between  the 
permanganate  and  oxalic  is  over,  add,  slowly  at  first,  50  c.c.  of 
i. 20  nitric  acid.  Heat  the  beaker,  and  if  the  solution  does  not 
become  perfectly  clear,  continue  to  add  a  few  more  crystals  of 
oxalic  acid.  Heat  until  all  brown  flakes  are  dissolved.  Then 
boil  ten  minutes;  cool;  and  proceed  as  when  standardizing  with 
standard  ferro-manganese.  As  explained,  weigh,  of  the  probable 
90  per  cent  sample  and  of  the  probable  42  per  cent  sample, 
enough  to  give  about  the  same  amount  of  iron  and  manganese 
as  in  the  standard  mixture.  Of  the  90  per  cent  sample  weigh, 
therefore,  0.500  gram  together  with  0.45  gram  of  the  muck  iron. 
(Electrolytic  *  iron  has  but  a  trace  of  manganese  in  it,  and  should 
answer  well  as  a  source  of  iron.)  Of  the  42  per  cent  sample  weigh 
i  gram,  but  add  no  extra  iron. 

If  the  1.3  grams  of  potassium  permanganate  require  193.8 
c.c.  of  the  ferricyanide  to  combine  with  it  and  give  the  blue  end 
as  described,  then  i  c.c.  of  the  ferricyanide,  in  the  presence  of 
approximately  0.500  gram  of  iron,  has  a  manganese  value  of 
1.3  X  0.994  X  0.34777  -^  193.8,  or  0.002318  gram.  As  the  so- 
called  c.p.  permanganate  of  potash  is  often  from  0.5  to  0.6  per 
cent  short  of  100  per  cent  purity,  hence  the  introduction  of 
the  factor  0.994. 

The  determination  of  any  amount  of  manganese  in  the  pres- 
ence of  Fe,  Ca  or  Mg  can  be  accomplished,  in  duplicate,  in 
3  hours'  time  by  this  process. 

The  purity  of  the  permanganate  can  be  checked  against  re- 
crystallized  c.p.  oxalic  acid  as  follows:  Dissolve  i  gram  of  the 

*  Electrolytic  iron  of  the  following  analysis  can  now  be  had:  Phosphorus, 
0.003  per  cent;  Sulphur,  trace;  Manganese,  0.02  per  cent;  Silicon,  0.003  per 
cent;  Carbon,  none. 


VOLUMETRIC   METHOD   FOR    MANGANESE  IN  IRON,   ETC.    199 

permanganate  in  150  c.c.  of  distilled  water,  acidulated  with 
100  c.c.  of  i  13  sulphuric  acid.  Warm  the  solution  slightly, 
and  add  to  it  2.0167  grams  of  the  oxalic  acid,  dissolved  in  150 
c.c.  of  distilled  water.  Warm  the  solutions  a  little,  if  necessary, 
until  the  mixture  of  oxalic  and  permanganate  has  become  color- 
less. Titrate  the  colorless  solution  with  a  dilute  permanga- 
nate standard  of  known  oxalic  value.  The  one  used  in  the 
analysis  of  crucibles  and  plumbago  answers  very  well,  i  c.c.  of 
this  standard  equals  0.00144  gram  of  oxalic  acid  (see  Analysis 
of  Graphite,  XVI,  page  338).  Suppose  25.5  c.c.  of  this  stand- 
ard are  required  to  render  the  decolorized  mixture  a  slight  pink 
that  will  remain  permanent  for  30  seconds,  therefore  25.5  X 
0.00144  or  0.0367  equals  the  excess  of  oxalic  acid  in  the  mixture. 
Hence  2.0167  —  0.0367  =  1.98,  or  the  amount  of  oxalic  acid 
oxidized  by  the  i  gram  of  the  permanganate.  By  the  equation 

2  KMnO4  +  5  H2C2O4  +  3  H2SO4 
=  K2SO4  +  2  MnSO4  +  8  H2O  +  10  CO2 

we  have  316.3  grams  of  KMnO4  =  630  grams  of  H2C204  -f- 
2  H2O,  or  oxalic  multiplied  by  0.502  equals  permanganate;  1.98 
X  0.502  =  0.99396,  or  the  i  gram  of  permanganate  contains 
0.9939  gram  of  100  per  cent  KMnO4.  The  precaution  must  be 
taken  to  use  sulphuric  acid  that  does  not  bleach  permanganate 
on  warming  a  few  drops  of  the  dilute  permanganate  standard 
with  150  c.c.  of  the  acid. 

In  using  potassium  ferricyanide,  it  must  be  remembered 
that  the  action  of  the  light  produces  a  blue  precipitate  in  it, 
and  ferrocyanide  forms  which  would  give  a  blue  with  any  little 
ferric  iron  that  might  be  present  in  the  indicator.  At  the  close 
of  the  titration  the  solution  must  still  smell  faintly  of  ammonia, 
and  an  excess  of  barium  carbonate  should  be  visible  in  the  bottom 
of  the  beaker.  As  long  as  the  clear  supernatant  fluid  clouds 
with  10  or  15  drops  of  the  standard  solution,  after  a  wait  of 
a  half  minute,  the  end  point  is  still  some  10  c.c.  distant.  As 
much  as  0.500  gram  of  pure  white  marble  together  with  o.ioo 
gram  of  metallic  magnesium  have  been  added,  as  nitrates,  to 


200 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


the  solutions  of  nitrate  of  iron  and  manganese  without  any 
apparent  effect  on  the  titration  of  the  manganese  in  the  solution. 
The  reaction  that  takes  place  between  the  manganese  and 
the  potassium  ferricyanide,  in  the  slightly  ammoniacal  solution, 
is  probably  analogous  to  the  one  between  ferrous  iron  and  the 
ferricyanide: 

2  KgFe  (CN)6  +  3  Mn  (NO3)2 
=  Mil,  [Fe  (CN)6]2  +  6  KN03. 


FERROUS  CHLORIDE  SOLUTION. 

This  solution  for  making  end  point  tests  can  be  conveniently 
prepared  from  a  low  carbon  steel  with  a  copper  content  under 
0.05  per  cent.  (If  the  steel  contains  too  much  copper,  it  will 
cloud  with  the  ferricyanide.)  Iron  wire  can  be  used.  Dissolve 
1.5  grams  of  the  wire  or  steel  in  20  c.c.  of  i  :  i  hydrochloric  acid, 
warming  gently.  When  the  solution  is  complete,  add  a  few 
grains  of  granulated  aluminum  to  entirely  decolorize  the  iron. 
Then  rinse  the  latter  into  a  500  c.c.  stoppered  flask  and  dilute 
to  250  c.c.  with  water.  It  is  well  to  make  the  ferrous  indicator 
fresh  each  day  that  it  is  needed.  Decant  the  2  c.c.  portions 
of  the  indicator  through  a  small  filter  to  remove  the  excess  of 
aluminum  just  before  using. 

The  author  proposes  to  work  out  similar  quantitative  volu- 
metric methods  for  the  assay  of  copper  and  zinc,  as  both  elements 
combine  speedily  with  the  potassium  ferricyanide  in  slightly 
acid  solutions. 


COMPARATIVE  RESULTS  BY  VOLHARD,  GRAVIMETRIC  AND  FERRICYANIDE 

METHODS. 


Gravimetric. 

Ferricyanide. 

Volhard. 

Carbonless  manganese 

(  QI  .  «CI 

(  01    ^8 

I  91.66 

|  91  .47 

High  carbon  ferro  

j  43  .  96 

j  43  .  74 

(  44  .  so 

Manganese  steel             

I  44-07 
13  .00 

U3-68 

12  .90 

(  44-05 

VOLUMETRIC  METHOD  FOR  MANGANESE  IN  IRON,  ETC.  2OI 

THE  TITRATION  OF  SOLUTIONS  FOR  MANGANESE  BY  A  STANDARD 
SOLUTION  OF  POTASSIUM  FERRICYANIDE  AFTER  REMOVING 
THE  IRON  BY  THE  BASIC  ACETATE  METHOD. 

After  removing  the  iron  by  the  basic  acetate  method,  as  given 
on  page  188  and  at  the  top  of  page  189,  the  combined  nitrates 
are  evaporated  to  20  c.c.  Then  add  i  :  i  ammonia  to  the  cold 
acetate  solution  until  it  will  just  turn  red  litmus  blue  and  then 
add  10  c.c.  of  the  ammonia  in  excess;  titrate  this  solution  with 
a  standard  ferricyanide  made  by  dissolving  7.50  grams  of  this 
salt  in  water  and  diluting  to  one  liter  for  ferro-manganese. 
One  c.c.  of  this  standard  should  equal  about  0.002174  gram  of 
manganese.  For  steels  containing  about  5  to  20  per  cent  of 
manganese,  use  a  standard  of  3.75  grams  of  the  ferricyanide  to 
the  liter,  which  should  have  a  value  of  close  to  0.001087  gram  of 
manganese  per  c.c.  In  the  absence  of  iron  the  change  of  factor 
value  required  to  compensate  for  the  error  due  to  the  presence 
of  iron  is  no  longer  required.  In  making  the  titration  as  given 
on  page  194  the  use  of  the  barium  carbonate  is  no  longer  required, 
and  the  end  points  are  gotten  with  a  saturated  solution  of  ferrous 
ammonium  sulphate  instead  of  ferrous  chloride.  This  is  a  very 
satisfactory  titration  but  must  be  made  in  the  absence  of  copper, 
nickel,  zinc  and  cobalt  which  can  be  removed  as  directed  on  page 
190  and  the  filtrate  evaporated  low  to  remove  hydrogen  sulphide, 
then  filtered,  this  filtrate  and  washings  are  diluted  by  200  c.c., 
and  the  analysis  is  finished  as  above.  The  titration  is  not  inter- 
fered with  by  calcium,  magnesium  or  barium  and  is  therefore 
particularly  advantageous  in  slag  analysis.  Chapter  X,  Part  II, 
should  be  carefully  read  before  proceeding  with  the  titration. 
Standardizations  are  made  by  putting  a  weighed  amount  of 
c.p.  permanganate  of  potassium  together  with  about  as  much 
iron  in  the  form  of  steel  drillings  (containing  a  known  manganese 
content)  as  there  is  in  the  sample  being  analyzed  through  all  of 
the  above  operations.  The  resulting  acetate  filtrate  is  titrated 
and  the  number  of  c.c.  of  the  ferricyanide  required  to  obtain  the 
end  point  is  divided  into  the  manganese  present  in  the  perman- 


202  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

ganate  taken  plus  that  contained  in  the  steel  drillings  used  to 
introduce  the  iron.  The  operator  can  also  standardize  by  adding 
the  main  manganese  in  the  form  of  standardized  ferro-man- 
ganese.  The  manganese  in  the  ferro  can  be  determined  by  the 
method  given  on  pages  188  and  189. 


CHAPTER  XL 

PART  I. 

THE  DETERMINATION  OF  CARBON  IN  IRON  AND  STEEL  BY 
DIRECT  IGNITION  WITH  RED  LEAD  OR  LITHARGE.* 

THE  writer's  experience  with  this  method  for  the  deter- 
mination of  carbon,  together  with  some  notes  on  what  led  to  its 
adoption  for  routine  combustion  analysis,  may  prove  of  interest. 

The  solution  of  steel  drillings  containing  large  percentages 
of  chromium,  tungsten  or  molybdenum  in  double  chloride  of 
copper  and  potassium  causes  more  or  less  loss  of  carbon  as  hydro- 
carbon. Especially  sensitive  to  such  loss  are  the  carbides  that 
are  separated  by  the  double  chloride  from  steels  in  which  are 
10  or  12  per  cent  of  molybdenum  together  with  several  per  cent 
of  chromium. 

These  carbides  may  lose  some  of  the  carbon  by  contact  with 
dilute  acid,  or  with  the  oxygen  of  the  air  during  washing  with 
suction,  or  during  the  subsequent  drying  of  the  carbide  at  the 
temperature  of  boiling  water. 

In  the  spring  of  1900  the  writer  made  an  analysis  for  carbon 
of  a  steel  containing  3.8  per  cent  of  chromium,  applying  the 
ordinary  method  |  of  dissolving  the  borings  in  acid  double 
chloride  of  copper  and  potassium,  filtering  on  an  asbestos  plug, 
washing  the  carbide  residue  alternately  with  distilled  water  and 
a  mixture  of  one  part  of  hydrochloric  acid  and  twenty  parts 
of  water.  The  residue  was  then  washed  with  water,  alone,  to 
remove  the  acid.  After  drying  the  washed  carbide  in  a  water 
oven,  it  was  burned  with  purified  oxygen  in  a  red  hot  porcelain 
tube  containing  about  13  cm.  of  copper  oxide.  The  products  of 

*  A  preliminary  paper  was  read  at  the  December,  1905,  meeting  of  the  Pitts- 
burg  Section  of  the  American  Chemical  Society, 
f  See  pages  246  to  250. 

203 


204 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


the  combustion  were  passed  through  granulated  zinc  of  20  mesh 
fineness,  then  through  anhydrous  calcium  chloride,  and  then 
through  phosphoric  anhydride.  The  purified  carbon  dioxide 
was  absorbed  and  weighed  in  potash  bulbs.  Duplicate  analyses 
by  this  method  failed  to  check. 

A  series  of  analyses  of  these  borings  were  made.  The  acid 
wash  when  used  was  alternated  with  distilled  water,  and  the 
washing  was  then  completed  with  distilled  water,  alone,  to 
remove  acid. 


Kind  of  Wash. 

Washings, 
Number. 

Carbon  Found, 
Per  cent. 

I 

20  parts  H^O  to  i  part  HC1 

i    6? 

2 

100  parts  H^O  to  i  part  HC1 

20  * 

I     ^2 

3  

100  parts  H^O  to  i  part  HC1  . 

2 

I    QOQ 

4  

100  parts  H2O  to  i  part  HC1 

2 

I    O4.3 

In  August,  1902,  the  process  used  in  the  foregoing,  (3)  and  (4), 
was  applied  to  a  steel  containing  4  per  cent  of  chromium  and 
4  per  cent  of  molybdenum  with  the  following  absence  of  agree- 
ment: 

First  analysis  gave  1.28  per  cent  carbon. 
Second  analysis  gave  i  .53  per  cent  carbon. 
Third  analysis  gave  1.33  per  cent  carbon. 
Fourth  analysis  gave  1.29  per  cent  carbon. 

The  thought  occurred  that  perhaps  the  carbide  obtained 
from  molybdenum  steel  gives  up  part  of  its  carbon  as  hydro- 
carbon on  being  brought  into  contact  with  the  air  during  stirring. 
No  heat  was  applied  to  hasten  the  solution  at  any  time.  A 
number  of  trial  analyses  were  made  in  which  the  time  of  stirring 
was  varied  and  also  the  acidity  of  the  copper  and  potassium 
chloride  solution.  In  the  following,  2  grams  of  the  drillings 
were  dissolved  in  180  c.c.  of  the  double  chloride  solutions.  By 
acid  solution  is  meant  a  solution  prepared  by  dissolving  600 
grams  of  double  chloride  of  copper  and  potassium  in  1500  c.c.  of 
distilled  water  acidulated  with  175  c.c.  of  concentrated  hydro- 
chloric acid.  By  nearly  neutral  solution  is  meant  the  same  as 


DETERMINATION  OF   CARBON  IN  IRON  AND   STEEL       205 


the  acid  solution  except  that  but  25  c.c.  of  concentrated  hydro- 
chloric acid  were  added  to  the  1500  c.c.  of  distilled  water. 

The  neutral  solution  consisted  of  600  grams  of  the  double 
chloride,  1500  c.c.  of  distilled  water,  and  no  acid.  The  results 
obtained  are  given  in  the  following  table: 

STEEL  CONTAINING  4  PER  CENT  MOLYBDENUM  AND  4  PER  CENT  CHROMIUM. 


Kind  of  Steels. 

Kind  of  Solvent. 

Time  of 
Stirring, 
Minutes. 

Time  in  the 
Solvent  with 
No  Stirring, 
Hours. 

Percentage 
of  Carbon 
Found. 

No.  i  steel... 

acid 

2O 

•  ^3 

No.  i  steel  

2O 

.48 

No.  i  steel  

« 

IO 

.64 

No.  i  steel  

« 

12 

•49 

No.  i  steel  

<  < 

24 

.52 

No.  i  steel  

nearly  neutral 

8 

.60 

No.  i  steel 

8 

re 

No.  i  steel.  .  . 

acid 

•2 

60 

No.  i  steel.  .  . 

neutral 

•     6 

CO  2 

No.  i  steel  

6 

.606 

No.  2  steel  

t( 

4 

I  .670 

No.  2  steel  
No.  2  steel 

acid 

6 

1-734 
I    7^8 

No.  2  steel.  . 

a 

4" 

i  66 

i 

A  combustion  of  the  4  per  cent  chromium,  4  per  cent  molyb- 
denum steel  (No.  2),  by  the  red  lead  process  described  below 
yielded  1.734  per  cent  carbon. 

An  examination  of  the  foregoing  table  shows  that  both  in  the 
No.  2  and  the  No.  i  steels  the  highest  result  was  obtained  when 
the  acid  solvent  was  used,  and  also  the  lowest  results. 

Short  stirring  gave  better  agreements  than  the  longer  periods 
of  stirring,  but  had  evidently  not  eliminated  all  of  the  causes  of 
loss.  Perhaps  there  is  loss  of  carbon  when  the  carbide  is  being 
dried  in  the  water  oven.  Further,  it  is  practically  impossible 
to  regulate  the  suction  so  as  to  expose  the  residues,  during 
washing,  to  exactly  the  same  amount  of  air  in  each  analysis. 

Two  grams  of  the  No.  2  steel  were  stirred  twenty  minutes 
with  1 80  c.c.  of  the  acid  solution,  then  transferred  to  the  asbestos 


206 


CHEMICAL  ANALYSIS   OF  SPECIAL  STEELS 


plug.  Air  was  next  drawn  through  the  residue  for  fifty  minutes; 
the  amount  of  carbon  obtained  was  1.347  per  cent.  Two  deter- 
minations of  the  same  steel  were  made  with  sixty  minutes'  stir- 
ring but  with  the  least  possible  exposure  to  air  by  suction;  1.63 
per  cent  and  i  .68  per  cent  carbon  were  found.  In  view  of  these 
results  the  practice  was  adopted  of  always  keeping  a  layer  of 
distilled  water  over  the  carbide  during  the  washing.  As  soon 
as  one  layer,  or  covering  of  water,  was  drawn  off,  another  was 
immediately  supplied. 

This  treatment  was  applied  to  a  group  of  ingots  containing 
ii  per  cent  molybdenum  and  some  chromium.  The  neutral 
solution  gave  the  higher  results,  as  shown  by  the  following 
table: 


Acid  Solvent. 

Neutral  Carbon. 

Per  Cent  Carbon. 

Per  Cent  Carbon. 

0.52 
0.46 

0.60 
0.56 

0-53 

0-59 

The  same  process  of  short  stirring  and  least  possible  exposure 
of  the  carbide  residue  to  air  by  suction,  together  with  the  use  of 
a  neutral  solvent,  was  adopted  for  a  series  of  ingots  containing 
12  per  cent  molybdenum  and  several  per  cent  of  chromium. 
It  failed  almost  completely.  For  convenient  comparison  the 
results  obtained  in  these  latter  experiments  are  shown  in  a  column 
parallel  to  those  obtained,  at  a  later  date,  from  the  same  sam- 
ples by  the  red  lead  combustion  method.  (Page  207.) 

One  well-known  laboratory  obtained  0.72  per  cent  carbon, 
and  another,  equally  experienced,  reported  0.64  per  cent  carbon 
on  the  S.  H.  S.  sample. 

This  untrustworthiness  of  the  double  chloride  process  for 
separating  carbon  in  steel  of  high  molybdenum  and  chromium 
content  led  to  a  search  for  some  method  of  obtaining  the  percen- 
tage of  carbon  by  burning  the  entire  substance.  Having  about 
this  time  noted  Brearley  and  Ibbotson's  statement  that  steel 


DETERMINATION  OF   CARBON  IN  IRON  AND   STEEL       207 


drillings  that  will  pass  a  2O-mesh  sieve  and  have  been  mixed 
with  about  three  times  their  weight  of  red  lead  can  be  decar- 
bonized in  a  red  hot  porcelain  tube,  it  was  decided  to  attack 
the  molybdenum  steel  in  this  manner.  The  results  obtained 
from  the  molybdenum  steels  are  given  in  the  table  below  and 
need  no  comment. 


Sample. 
12  Per  Cent  Mo. 
Steel  Containing  Cr. 

Results  Obtained 
by  the  Neutral 
Solution.     Per 
Cent  Carbon. 

Results  by  the 
Red  Lead  Process. 
Per  Cent  Carbon. 

No.  i               

jo.  54 

0.80 

No.  2  

1  0.72 
i  0.81 

0.79 
o  76 

No.  3.. 

(  0.51 
(0.66 

o  82 

No.  4 

'  0.51 
$0.54 

o  81 

"  2d  trial"  

(0.58 
Jo.  47 

j  0.88 

No.  5.. 

{  0.61 
jo.6i 

to.  85 
(0.88 

No.  6  

1  0.88 

10.87 

072 

S.  H.  S. 

(0.69.88 
<  o  66 

No.  7  

(0.68.75 
(  0.66 

0.94 

No   10 

1  0.52 
(0.76 

0-939 

No.  ii 

}  °-  75 

(0.62 
jo.  72 

o  80 

|0.52 

The  method  was  first  applied  to  plain  carbon  steels,  pig  iron, 
and  white  iron,  and  was  found  to  be  perfectly  accurate. 

After  more  than  eighteen  months'  daily  use  of  the  red  lead 
for  the  determination  of  carbon  in  steel,  pig  iron,  alloy  steels, 
and  ferro  alloys,  the  details  that  have  been  found  useful  and 
reliable  are  as  follows: 

If  part  of  the  borings  are  coarse,  the  thin  curly  portions  or 
30  to  60  mesh  sievings  are  selected.  Two  grams  of  such  drillings 
and  2  grams  of  the  red  lead  are  weighed  into  a  glass  stoppered 


208  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

60  c.c.  weighing  bottle.  The  bottle  is  then  shaken  to  mix  the 
drillings  and  lead  oxide. 

The  steel  sample  submitted  for  analysis  is  drilled  with  a  flat 
or  diamond  pointed  drill.  This  style  of  drill  will  grind  many 
of  the  drillings  to  20  mesh  fineness  in  the  case  of  soft  or  annealed 
steels.  If  the  steel  be  unannealed  and  of  a  carbon  content 
ranging  from  about  0.35  per  cent  carbon  and  higher,  thin  curly 
drillings  are  obtained  which  decarbonize  readily  by  reason  of 
thinness.  If  the  drillings  do  not  exceed  20  mesh,  as  in  siftings, 
4  grams  of  red  lead  will  completely  decarbonize  4  grams  of  the 
steel.  Care  is  taken  at  all  times  to  cover  bulky  drillings  with 
the  oxide  of  lead,  as  any  drillings  that  project  above  the  main 
body  of  the  charge  are  likely  to  escape  oxidation. 

For  soft  steels  and  annealed  steels  two  sieves  are  used.  One 
lias  a  20  mesh  gauze  and  the  other  one  a  60  mesh  gauze.  Those 
drillings  that  pass  the  20  mesh  gauze  but  do  not  pass  the  60 
mesh  sieve  are  used  for  analysis. 

This  arrangement  rejects  the  fine  dust  and  the  thick  drillings. 
When  very  small  pieces  of  steel  are  received  they  are  drilled  with 
-fs  inch  diameter  twist  or  straight  drills.  All  sizes  of  the  flat, 
or  diamond  point,  drills  are  kept  at  hand  from  \  inch  diameter 
to  |-  inch.  Any  good  mill  blacksmith  can  make  the  flat  drills. 
By  these  means  it  is  rarely,  if  ever,  necessary  to  resort  to  the  cop- 
per and  potassium  chloride  separation  of  the  carbon.  In  the  lab- 
oratory of  the  Park  Steel  Co.,  where  many  combustions  are  made 
each  day,  covering  a  range  from  0.04  to  3.5  per  cent  carbon,  the 
writer  does  not  recall  more  than  a  single  instance  in  a  year's  time 
when  it  was  necessary  to  resort  to  the  double  chloride  process. 

The  mixture  of  lead  oxide  and  drillings  is  transferred  from 
the  weighing  bottle  to  porcelain  boats.*  The  Royal  Meissen 
brand,  15  X  75  mm.  or  112  X  12  mm.,  is  mostly  used,  being 
convenient  sizes.  The  porcelain  boats  are  slipped  into  f  por- 

*  The  author  now  uses  the  clay  boats  for  all  combustions,  and  clay  tubes. 

f  f  inch  inside  diameter  fused  silica  tubes  are  very  desirable  for  this  work. 
The  litharge  fumes  and  spills,  however,  will,  in  time,  destroy  them.  The  writer 
sometimes  uses  a  small  inner  cylinder  of  platinum  just  large  enough  to  hold  the 
boat.  Iron  oxide  will  flux  silica  tubes.  (See  clay  tubes,  page  243.) 


DETERMINATION  OF    CARBON   IN   IRON   AND    STEEL      2OQ 


celain  tubes*  of  16  mm.  inside  diameter  X  600  mm.  long.  Two 
furnaces  with  their  porcelain  tubes  are  operated  at  the  same 
time.  Until  recently,  the  outlet  ends  of  these  tubes  were  filled 
for  a  distance  of  125  mm.  with  granulated  copper  oxide.  Later 
the  copper  oxide  was  found  to  be  unnecessary.  Oxygen  is  used 
during  the  combustion.  It  passes  through  a  jar  containing 


FIG.  4. 


FIG.  5. 


pieces  of  caustic  potash  (Fig.  4).  It  next  bubbles  through  a  solu- 
tion of  potassium  hydroxide  contained  in  a  safety  apparatus  (Fig. 
5),  and  is  then  dried  in  jars  of  soda-lime  and  calcium  chloride 
of  the  design  given  in  Fig.  4.  This  drying  and  purifying  appa- 
ratus can  be  readily  arranged  and  securely  fastened  in  a  space 
250  X  406  mm. 

The  combustions  are  operated  in  the  usual  manner.  The 
portion  of  the  tube  containing  the  copper  oxide  is  heated  to 
redness,  and  then  the  remainder  of  the  tube  lying  within  the 
furnace  is  brought  to  the  same  temperature.  The  combustion 
tubes  are  constantly  kept  hot  through  half  the  length  so  that 
the  combustion  commences  almost  as  soon  as  the  stoppers  are 
inserted.  While  the  boats  are  being  charged  the  oxygen  is  pass- 
ing slowly  through  the  tubes  and  the  weighing  and  absorbing 
apparatus  which  has  been  previously  weighed  and  attached. 

*  The  author  is  now  using  tapered  clay  combustion  tubes.     (See  page  243.) 


2IO 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


FIG.  6. 


(This  weighing  apparatus  is  shown  in  Fig.  6.  It  was  designed 
by  the  writer  as  a  substitute  for  the  different  forms  of  potash 
bulbs  now  in  the  market.  It  is  made  of  heavy  glass.  It  is 
easily  kept  clean,  is  not  top-heavy,  and  does  not  occupy  much 
space  in  a  balance  case.)  As  soon  as  the 
steel  begins  to  burn,  there  is,  at  first, 
a  rapid  evolution  of  gas  which  quickly 
ceases.  More  oxygen  is  then  turned  into 
the  apparatus  from  the  steel  cylinder  so 
that  a  slow  bubbling  is  maintained  through 
the  weighing  apparatus.  When  the  oxi- 
dation of  the  charge  is  completed,  the 
oxygen  begins  to  rush  through  the  ap- 
paratus at  a  high  rate  of  speed.  The  flow 
of  the  gas  is  quickly  checked  to  a  normal 
rate,  that  is,  it  is  checked  so  that  it  passes 
through  the  safety  apparatus  (Fig.  5)  at 
a  rate  of  about  26  bubbles  per  10  sec- 
onds. The  stream  is  evenly  distributed  to  the  two  com- 
bustion tubes  by  means  of  a  Y-tube  and  screw  pinch-cocks. 
The  stream  passes  through  the  weighing  apparatus  (Fig.  6) 
at  the  rate  of  250  c.c.  every  ten  minutes,  which  is  the  normal 
speed.  When  the  combustions  are  completed  in  both  sets  of 
apparatus,  as  indicated  by  the  passage  of  the  gas  at  a  high  rate 
of  speed,  the  normal  is  then  maintained  through  the  red  hot 
tubes  10  minutes  longer  to  insure  complete  oxidation  and  that 
all  of  the  carbon  dioxide  has  been  carried  to  the  weighing  appa- 
ratus. The  products  of  the  combustion  pass  through  a  purifying 
train  shown  in  Fig.  7.  The  train  connects  with  the  glass  tube 
leading  from  the  outlet  end  of  the  porcelain  combustion  tube, 
by  means  of  heavy  combustion  rubber  tubing,  at  H.  The  gases 
pass  through  the  cylinder  /  which  contains  a  column  of  granu- 
lated zinc  of  20  mesh  fineness.  The  use  of  granulated  zinc  to 
remove  acid  and  chlorine  in  carbon  combustions  was  first  sug- 
gested by  Dr.  Edward  S.  Johnson.  Cylinder  I  is  254  X  13  mm. 
The  zinc  is  held  in  place  with  plugs  of  glass  wool.  The  gases 


DETERMINATION  OF   CARBON   IN  IRON  AND   STEEL       21 1 

next  enter  a  cylinder  /  which  contains  a  column  of  phos- 
phoric anhydride.  The  phosphoric  anhydride  powder  is  held 
in  place  with  plugs  of  ignited  asbestos.  Cylinder  /  is  178  X  13 
mm.  Glass  wool  plugs  should  not  be  used  in  /,  as  they  become 
clogged,  after  a  few  combustions.  Ignited  asbestos  is  free  from 
this  objection. 

The  carbon  dioxide,  which  is  now  freed  from  litharge  and 
sulphur,  and  any  acid  fumes  by  zinc,  and  from  any  moisture 


FIG.  7. 

by  the  phosphoric  anhydride,  enters  the  weighing  apparatus 
L.  This  weighing  apparatus,  as  shown  in  the  complete  train 
(Fig.  7),  differs  slightly  from  the  writer's  first  design  shown  in 
Fig.  6.  The  apparatus  is  charged  with  20  c.c.  of  potassium 
hydroxide  consisting  of  one  part  of  caustic  potash  dissolved  in 
i  part  of  water.  The  drying  tube  C,  Fig.  6,  is  filled  with 
small  pieces  of  dry  caustic  potash  obtained  by  quickly  cracking 
dry  sticks  of  caustic  potash  in  a  porcelain  mortar.  Each  end 
of  the  drying  tube  C  contains  a  plug  of  asbestos  or  glass  wooL 
Before  inserting  the  rubber  stopper  in  C,  care  must  be  taken  to 
free  the  surface  of  the  tube  C  from  any  moist  caustic  potash,  as 
potassium  hydroxide  causes  decomposition  of  rubber,  resulting 
in  continuous  loss  of  weight. 


212  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  weighing  apparatus  is  ready  for  recharging  at  the  end  of 
the  fortieth  combustion.  The  tare  is  then  used  for  the  absorb- 
ing and  weighing  of  the  carbon  dioxide  obtained  from  the  next 
40  combustions,  the  exhausted  apparatus  now  constituting  the 
tare. 

During  the  passage  of  the  oxygen  the  outlet  0,  Fig.  7,  is 
protected  from  the  ingress  of  moisture  or  impure  air  by  a  guard 
tube  filled  with  small  pieces  of  caustic  potash.  This  guard 
tube  is  not  shown  in  Fig.  7.  All  parts  of  the  apparatus  shown 
in  Fig.  7  are  connected  by  heavy  wall  pure  rubber  tubing. 

When  the  combustions  are  completed  the  weighing  apparatus 
is  detached  from  its  train,  and  the  outlet  of  the  train  is  closed 
with  a  glass  plug. 

It  is  accurate  to  weigh  the  absorption  apparatus  (Fig.  6) 
filled  with  oxygen  and  thus  avoid  aspirations.  In  this  way 
combustions  can  be  carried  through  in  25  minutes. 

The  apparatus  and  its  tare  are  next  carefully  wiped  with  a 
clean  linen  handkerchief  and  are  placed  in  the  balance  case  for 
weighing.  The  inlet  and  outlet  of  the  weighing  apparatus  are 
kept  closed  with  rubber  caps  except  during  weighings  or  when 
attached  in  the  train  (Fig.  7). 

The  method  of  using  an  exact  duplicate  of  the  weighing 
apparatus  for  a  tare  exposes  the  same  amount  of  surface  to  the 
air  during  weighings  and  avoids  the  use  of  the  larger  weights. 

As  previously  stated  the  porcelain  tubes  are  kept  red  hot 
throughout  one-half  their  length  night  and  day  so  that  the  com- 
bustion commences  in  a  minute  or  two  after  the  boat  is  in- 
serted and  the  combustion  tube  is  stoppered.  The  remaining 
burners  are  lighted  immediately  after  the  tube  is  closed. 

*The  red  lead  used  in  this  work  must  be  thoroughly  mixed 
and  ground  free  of  lumps  before  its  carbon  content  is  deter- 
mined. The  so-called  pure  red  lead  costing  about  9  cents 

*  On  one  occasion  a  lot  of  red  lead  was  purchased  that  was  not  uniform. 
No  amount  of  mixing  improved  it.  It  was  rejected.  Subsequent  kegs  gave  no 
trouble.  Good  commercial  red  lead  gives  about  0.004  gram  of  COa  per  4  grams, 
and  is  very  uniform. 


DETERMINATION  OF   CARBON  IN  IRON  AND    STEEL      213 

per  pound  in  50  pound  lots  is  found  satisfactory  for  the  purpose. 
Blank  combustions  with  4  grams  of  red  lead  are  at  present 
yielding  6  mgs.  of  carbon  dioxide  which  are  deducted  from  each 
determination.  Blank  combustions  or  analyses  of  standard 
steels  should  be  made  each  day.  The  red  lead  is  kept  in  tightly 
stoppered  bottles. 

The  method  of  weighing  the  carbon  dioxide  obtained  in 
the  red  lead  combustions  as  barium  carbonate  was  tried  for 
several  months.  As  it  is  not  necessary  to  dry  the  carbon  dioxide 
in  this  modification  of  the  red  lead  method,  the  carbon  dioxide 
was  passed  through  a  cylinder  illustrated  by  Fig.  4  filled  with 
granulated  zinc  to  remove  litharge  fumes,  and  from  thence 
the  carbon  dioxide  entered  the  absorbing  apparatus,  which  con- 
sisted of  two  254  X  25.4  mm.  test  tubes  connected  in  tandem 
and  containing  barium  hydroxide  solution.  The  solution  in  the 
first  tube  converts  the  bulk  of  the  carbon  dioxide  formed  into 
barium  carbonate,  but  in  the  higher  carbon  steels  a  little  escapes 
into  the  second  tube. 

The  barium  carbonate  is  filtered  through  12  cm.  filters  rein- 
forced at  the  apex  by  a  piece  of  cheese-cloth.  The  precipitate 
is  washed  30  times  with  distilled  water,  allowing  each  washing 
to  be  drawn  off  by  slight  suction. 

The  cheese-cloth  is  removed  and  the  precipitate  is  ignited 
and  weighed.  From  this  weight  the  amount  of  barium  carbonate 
formed  from  the  impurities  in  the  red  lead  and  that  obtained 
from  the  unavoidable  exposure  of  the  excess  of  the  hydroxide 
during  filtration  and  washing  is  deducted.  From  the  net  weight 
of  barium  carbonate  the  percentage  is  calculated. 

The  barium  hydroxide  solutions  are  prepared  by  dissolving, 
or  nearly  dissolving,  200  grams  of  barium  hydroxide  crystals 
in  4  liters  of  water.  It  is  filtered  by  suction  through  a  paper 
pulp  filter  and  preserved  with  the  usual  precautions.  The 
test  tubes  for  the  solution  are  provided  with  30  c.c.  and  70  c.c. 
marks.  The  pair  of  tubes  constituting  the  absorption  pair  are 
filled  to  the  30  c.c.  marks  with  water,  and  the  barium  hydroxide 
solution  is  then  poured  in  until  the  70  c.c.  marks  are  reached. 


214  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

A  protracted  comparison  of  the  two  gravimetric  processes 
described  in  this  paper  extending  over  a  period  of  several  months 
was  made.  The  method  whereby  the  resultant  carbon  dioxide 
was  weighed  as  barium  carbonate  checked  excellently  with  the 
one  in  which  the  carbon  dioxide  was  absorbed  and  weighed  in 
the  apparatus  shown  in  either  Fig.  6  or  in  the  termination  of  the 
train,  Fig.  7,  agreeing  within  o.oi  per  cent  or  less.  The  latter 
(KOH)  process  is  preferred  as  requiring  less  manipulation,  less 
oxygen  and  less  time.  In  the  barium  carbonate  method  it  was 
necessary  to  force  the  oxygen  through  the  safety  apparatus 
(Fig.  5)  at  the  rate  of  38  bubbles  per  10  seconds  on  account  of 
the  resistance  to  the  passage  of  the  gas  through  the  absorption 
test  tubes. 

The  ordinary  lo-burner  Bunsen  combustion  furnace  is  em- 
ployed, but  with  certain  alterations  to  secure  higher  heating 
power.  At  the  points  where  the  porcelain  tubes  rest  in  the  ends 
of  the  furnace  these  ends  are  slotted  down  about  25  mm.  This 
permits  the  tubes  to  lie  well  enveloped  with  the  flames.  Further, 
under  each  foot  of  the  furnaces  pieces  of  fire-brick  about  28  mm. 
thick  are  placed.  Also  the  rows  of  burners  are  lowered  until 
they  rest  on  the  laboratory  table.  To  keep  the  rows  vertical 
one  burner  at  each  end  of  the  rows  is  wired  to  the  furnace.  This 
lowering  of  the  burners  and  raising  of  the  furnace  frame,  by  use 
of  the  fire-brick,  improves  the  draught  and  secures  hot  flames 
with  a  minimum  gas  pressure.  Strips  of  wet  cheese-cloth  about 
25  mm.  wide  are  wrapped  around  the  ends  of  the  porcelain 
tubes  to  keep  the  rubber  stoppers  from  burning.  The  ends  of 
these  strips  dip  into  suitable  vessels  of  water. 

Porcelain  tubes  glazed  inside  only,  of  16  mm.  inside  diameter 
by  600  mm.  long,  will  last  from  6  weeks  to  2  months  when  in 
use  night  and  day.  Flames  are  always  kept  under  the  tubes. 
Such  tubes  cost  about  $3.00  each.  (See  clay  tubes,  page  243.) 

Porcelain  boats  are  cleaned  for  further  use  by  allowing  them 
to  stand  in  nitric  acid  of  1.20  sp.  gr.  for  some  hours.  The  boats 
are  ignited  a  few  minutes  in  the  flame  of  a  Bunsen  burner  just 
before  being  used.  Porcelain  boats  14  to  15  mm.  wide  by  from  70 


DETERMINATION  OF   CARBON  IN  IRON  AND   STEEL       215 


to  75  mm.  long,  Royal  Meissen  brand,  are  quoted  in  10  gross  lots 
at  $14.50  per  gross.  These  boats  can  be  used  3  times.* 

The  apparatus  shown  in  Fig.  5  was  designed  as  a  safety 
apparatus  to  prevent  the  potassium  hydroxide  solution  from 
blowing  over  into  the  rubber  tubing  from  any  cause.  The 
oxygen  enters  the  chamber  E  and  bubbles  through  chamber 
F,  which  is  filled  to  ^  its  capacity  with  potassium  hydroxide 
solution  consisting  of  i  part  of  caustic  potash  dissolved  in  i 
part  of  water.  F  is  35  mm.  outside  diameter  by  170  mm.  long. 
Fig.  4  shows  a  tower  or  jar  that  is  used  as  a  container  for  small 
pieces  of  stick  caustic  potash  for  purifying  the  oxygen.  The 
pieces  of  apparatus  shown  in  Figs.  4,  5  and  7  were  designed  by 
the  writer  to  avoid  the  use  of  rubber  stoppers. 

fThe  following  results  attest  the  accuracy  of  the  red  lead 
process : 


Name  of  Sample. 

Weight  of 
Sample 
Taken, 
Grams. 

Weight  of 
Lead 
Oxide 
Used, 
Grams. 

Per  Cent 
Carbon  by 
Red  Lead. 

Per  Cent 
Carbon  by 
Double 
Chloride. 

S   S.  Co.  carbon  steel 

? 

O   O^Qcj 

O  41  *» 

No.  690. 

o  08"? 

o  06 

No.  350,  tungsten  steel  

I    28^ 

I    20 

No.  353,  tungsten  steel  

1.338 

I    3^4. 

No.  22,  high  per  cent  nickel  steel.  . 

0.6q8 

o  696 

No   14,  nickel  steel. 

O   4.4.7 

O   4^O 

S  XIX,  high  per  cent  tungsten  steel 

i  2.40 

2    2C 

Wash  metal          

l| 

15 

(2.39 
j  3-  56 

•2    en 

Wash  metal  

l| 

2 

13-65 
3   58 

C.  B.  pig  metal  .  .  .  -.  

li 

3f 

4  01 

C.  B.  pig  metal  

i| 

li 

4.04 

4  °4 

Soft  O  H   steel  No   i 

6 

o  192 

o  185 

Soft  O.  H.  steel  No.  2 

8 

4" 

O  O07 

O  O77 

Soft  O.  H.  steel  No.  3761  

6 

3 

0.156 

0.145 

In  July,  1901,  a  sample  of  steel  was  sent  by  Sanderson  Bros. 
Steel  Works  to   several  laboratories.     The  writer  retained  a 

*  The  author  uses  clay  boats  exclusively  for  carbon  determinations, 
f  Reprinted  from  The  Journal  of  the  American  Chemical  Society  (with  addi- 
tions), Vol.  XXVIII,  No.  7,  July,  1906. 


2l6  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

portion   of    these    drillings    for    several   years.     The    different 
laboratories  reported  as  follows: 

Per  Cent  Carbon. 

,  Atha  Steel  Works  obtained 25 

Crescent  Steel  Works  obtained 20 

Park  Steel  Works  obtained 214 

Spaulding  Jennings  Steel  Works  obtained 199 

Sanderson  Bros.'  Work^  obtained 214 

La  Belle  Steel  Co.'s  Works  obtained 20 

3  grams  of  this  sample  plus  i .  5  grams  of  red  lead  burned  in  stream 

of  oxygen  gave 1.22 

In  March,  1901,  the  following  parties  reported  the  carbon  of 
another  sample  of  steel: 

Per  Cent  Carbon. 

Booth,  Garret  &  Blair  reported 277 

Sanderson  Bros,  reported 292 

Park  Steel  Co.  reported 301 

Bethlehem  Steel  Co.  reported 307 

Crescent  Steel  Co.  reported , .315 

3  grams  of  this  sample  decarbonized  with  i .  5  grams  of  red  lead 

yielded i  .305 

The  writer  has  since  had  occasion  to  compare  results  with 
other  laboratories  covering  a  range  in  carbon  from  0.32  to  1.45 
per  cent  carbon  with  equally  good  agreements. 


CARBON  IN  FERRO-CHROMIUM. 

In  applying  the  red  lead  process  to  ferro-chromium,  it  was 
found  that  the  maximum  carbon  in  the  65  per-  cent  chromium 
alloy  was  obtained  by  burning  the  alloy  with  3  to  4  times  its 
weight  of  red  lead.  (See  table  at  top  of  page  217.) 

A  red  hot  body  of  copper  oxide  hastens  breakage  of  porce- 
lain tubes  by  causing  unequal  cooling  strains  when  the  furnace 
flames  are  lowered  or  extinguished  for  any  reason.  Since 
February,  i  tube  has  been  in  use  without  copper  oxide.  The 
oxide  is  still  retained  in  the  companion  tube,  so  that  daily  com- 
parisons have  been  made. 


DETERMINATION  OF  CARBON  IN  IRON  AND   STEEL      217 


Ferro-chrome. 


Weight  of 

Sample  Taken, 

Grams. 


Weight  of  Red 

Lead  Used, 

Grams. 


Per  Cent 
Carbon  Found. 


Sample  A. 


Sample  E. 


Sample  B 

Sample  C 

Sample  D 


3* 

i 

! 

2 

4 
3 

4 
4 


7.26 

7-54 
7.72 

7-73 
7-03 
7..  oo 
6.46 

6-55 
6.05 

5-17 

6.403 

7.094 

7-15 

7.07 

7.18 


In  February,  1906,  the  copper  oxide  was  omitted  from  i 
combustion  tube.  The  space  ordinarily  occupied  with  copper 
oxide  was  filled,  loosely,  with  ignited  asbestos.  The  following 
results  indicate  that  the  use  of  copper  oxide  in  combustions 
with  red  lead  is  unnecessary: 


Sample. 


With  Copper 

Oxide. 
Per  cent  Carbon. 


Without  Copper 

Oxide. 
Per  cent  Carbon. 


3  square  steel i .  479 

No.  288 i .  175 

6  S o.  207 

No.  1193 0.712 

No.  7013 0.520 

C.  No.  2 1.48 

No.  2703 0.316 

No.  385 0.425 

No.  7014 o .  396 

No.  7013 o .  401 

No.  1 241 o .  75 

C.  No.  3 1.281 

No.  7015 0.409 

No.  7016 0.481 

No.  7017 0.312 

No.  7018 0.425 

No.  7020 0.431 

No.  1 200 o .  73 

Ferro-manganese 6.31 

Mixture  of  plumbago  and  clay 45.96 

Pig  iron  "  B  " 3.61 


1-477 

I-I75 

0.207 

0.692 

0.538 

i-5i 

0.309 

0-439 
0-393 
0-397 
0.765 
1.283 
0.407 
0.478 
0-315 
0-43 
0-431 
0-75 
6-39 
46.04 
3.58 


2l8  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Since  writing  this  article  the  author  has  tried  litharge  as  a 
substitute  for  red  lead  and  has  found  that  it  possesses  some 
advantages  over  the  latter,  being  less  destructive  of  boats  and 
tubes.  It  is  in  general  more  pleasant  to  handle.  Two  grams  of 
litharge  to  the  same  weight  of  steel  are  sufficient  where  sif  tings  of 
from  20  to  60  mesh,  or  thin  drillings  that  can  be  packed  in  a  close 
mass,  are  obtainable.  It  is  extremely  rare  that  such  a  sample 
cannot  be  gotten  if  the  chemist  will  only  insist  that  a  piece  of 
the  steel  be  sent  to  him  instead  of  drillings  that  frequently  are 
coated  with  a  film  of  grease,*  or  contain  bits  of  paper,  fine  fibers 
of  wool  waste,  leaf  tobacco,  blue  steel,  rust,  scale,  or  clay.  He 
can  then  take  his  own  drillings  with  the  proper  absence  of 
variety.f  Most  chemists  are  aware  that  the  center  of  the  cross 
section  of  a  square  bar  or  round  piece  of  steel  often  contains  as 
much  as  50  per  cent  more  phosphorus,  sulphur  and  carbon 
than  the  outside  part.  Further,  that  sheet  steel  just  as  often 
varies  as  much  in  these  elements,  and  in  spots:  Hence,  to  get 
an  average  and  fair  sample,  a  square  bar  or  a  round  one  should  be 
drilled  from  the  surface  toward  the  inside,  either  halfway  or  all 
of  the  way  through  the  sample  when  practicable. 

If  for  any  reason  the  steel  must  be  drilled  on  end  then  a  row 
of  holes  of  equal  depth  should  be  drilled  all  of  the  way  across 
the  section  and  all  of  the  drilling  mixed  together.  In  like 
manner  a  flat  bar  or  sheet  should  have  a  series  of  holes  of  the 
same  depth  drilled  across  it  from  edge  to  edge.  A  failure  to 
observe  these  precautions  often  results  in  disputes  between 
buyer  and  seller. 

*  Clean  greasy  or  oily  drillings  by  repeated  extractions  with  ether.  Place 
the  drillings  in  a  small  weighing  bottle  and  shake  them  up  with  enough  ether 
to  cover  them.  The  ether  will  become  yellow  if  the  drillings  are  greasy.  Pour 
this  ether  off.  Pour  on  some  clean  ether  and  repeat  the  extraction;  pour  off,  and 
so  on,  until  the  ether  is  no  longer  colored.  This  process  removes  lint  at  the  same 
time,  as  one  can  readily  notice.  The  fluid  will  be  seen  to  be  full  of  many  short 
fibers,  at  times. 

t  Another  cause  of  variable  results  is  surface  decarbonization,  or  bark.  When 
steel  shows  bark  all  drillings  should  be  rejected  until  the  drill  passes  through  the 
decarbonized  zone.  If  the  sample  is  too  thin  for  this  precaution,  then  the  con- 
dition of  the  steel  should  be  noted  on  the  chemist's  report.  See  pages  348  to  355 
on  the  cause  of  bark. 


DETERMINATION  OF  CARBON  IN  IRON  AND  STEEL'     219 


220 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


It  is  surprising  from  what  small  and  hopeless  looking  pieces 
of  steel  one  can  extract  enough  drillings  of  the  proper  cross 
section  for  direct  combustion  analysis  with  a  good  assortment 
of  small  drills  and  a  little  experience. 

THE  TAKING  OF  DRILLINGS   OR  MILLINGS   SUITABLE  FOR 

ANALYSIS. 

In  this  connection  one  should  read  the  remarks  at  the  close 
of  Chapter  XI,  Part  i.  (Page  218.)  Fig.  8  shows  a  drill 
press  operated  with  a  direct  connected  constant  speed  motor 


FIG.  9. 

of  3!  horse  power.  The  press  is  equipped  with  an  adjustable 
vise  which  can  be  turned  at  any  angle  so  that  small  and  very 
irregular  pieces  of  steel  can  be  gripped  and  held  immovable 
during  the  drilling.  The  drill  chuck  is  large  enough  so  that 
the  set  screw  that  holds  the  drill  in  place  does  not  protrude, 
thereby  preventing  any  possibility  of  the  operator  getting  his 
sleeve  caught  and  his  arm  twisted  around  the  spindle.  To 
prevent  particles  of  oil  or  grease  from  getting  in  the  drillings, 
thereby  ruining  the  same  for  the  determination  of  carbon  by 


DETERMINATION  OF   CARBON  IN  IRON  AND    STEEL      221 

combustion,  the  author  had  a  large  disk  of  sheet  iron  put  on  top 
of  the  chuck  as  shown.     This  precaution  proved  invaluable. 

Fig.  9  gives  the  author's  device  for  sampling  material  that 
cannot  be  drilled  by  reason  of  extreme  thinness  of  cross  section. 
At  this  writing  quite  a  number  of  copies  of  this  tool  are  in  use 
both  at  home  and  abroad. 

LABORATORY  MILLING  MACHINE  FOR  SAMPLING  STEEL. 

Reprinted  from  Journal  of  Industrial  and  Engineering  Chemistry. 

In  certain  kinds  of  steel  the  writer  encountered  much  difficulty 
in  getting  samples  of  sufficiently  small  mesh  for  the  determina- 
tion of  carbon  by  the  direct  method  described  by  him  several 
years  ago. 

The  trouble  was  confined  to  thin  sheets,  wire,  hack-saw  steel, 
band-saw  steel,  razor  blades,  resistance  ribbon,  nails  and  small 
samples  of  all  kinds  that  are  irregular  in  shape  and  difficult  to 
hold  in  the  drill  press  vise. 

The  machine  shown  in  the  illustration  afforded  a  successful 
means  of  avoiding  various  time  consuming  expedients. 

The  sample  D  of  wire,  for  example,  is  held  in  the  vise  V-V. 
The  millings  are  taken  by  means  of  a  cutter,  made  of  the  best 
high-speed  steel,  and  are  caught  on  a  piece  of  cardboard  at  C. 

The  automatic  feeding  device  at  A  is  hastened  in  its  action  by 
tightening  the  screw  at  B. 

If  millings  are  taken  from  very  small  gauge  wire,  a  large 
sample  can  be  obtained  more  quickly  by  twisting  the  strands 
together  after  cleaning  the  same  with  emery  cloth,  if  rusty.  In 
this  way  the  cutter  mills  as  many  lengths  as  desired  at  one 
time.  This  machine  mills  copper  wire  with  great  ease.  It 
makes  easy  the  getting  of  the  large  quantity  of  material  required 
for  the  determination  of  oxygen  in  copper,  for  example.  In 
like  manner,  when  it  is  desired  to  expedite  the  taking  of  large 
samples  from  extra  thin  sheets  of  metal,  these  sheets  can  be 
cut  in  strips  with  tinner's  shears.  The  strips  from  the  same 
sheet  can  then  be  laid  one  on  the  other,  clamped  in  the  vise,  in 
layers,  and  all  milled  at  once. 


222  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  milling  cutter  can  be  sharpened  several  times. 

It  is  desirable,  and  well  worth  the  small  amount  of  time  in- 
volved, to  anneal  all  samples  received,  if  they  are  not  already 
in  a  softened  state.  This  operation  can  be  done  in  a  half  hour's 
time  by  heating  the  sample  to  800°  C.  (bright  red),  quenching 
at  once  in  water  and  then  holding  at  620°  to  630°  C.,  for  20 
minutes  (low  red).  Samples  that  cannot  be  quenched  for  any 
reason  should  be  annealed  as  described  under  Annealing,  pages 
339  to  354.  The  annealing  of  13  per  cent  manganese  steel  has 
also  been  previously  described  in  "Analysis  of  Special  Steels, 
etc.,"  together  with  the  chemical  tests  for  perfect  annealing. 

The  millings  obtained  by  this  laboratory  tool  are  not  sifted, 
as  they  are  just  right  for  direct  determination  of  carbon  by 
combustion  in  oxygen. 

If  the  sample  submitted  is  sufficiently  rigid,  it  does  not  need 
to  be  held  by  both  ends,  as  in  the  case  of  the  sample  of  wire. 

This  machine,  as  illustrated,  has  been  in  use  in  the  writer's 
laboratory  for  a  year.  Since  its  introduction,  the  samplers  no 
longer  dread  the  appearance  of  wire  and  steel  ribbon,  this  work 
being  now  a  mere  matter  of  easy  routine. 

The  first  cost  was  a  bagatelle  compared  to  the  saving  of  labor 
in  i  month.  Several  copies  of  this  milling  tool  are  now  in  use 
in  other  laboratories  of  this  company. 

THE  TAKING  OF  DRILLINGS  OR  MILLINGS. 

Hard  and  Soft  Layers. 

Samples  of  steel  are  frequently  submitted  that  consist  of 
welded  layers  of  hard  and  soft  steel,  such  as  soft-center,  3- 
ply  knife,  inserted  and  overcoat  axe  bit,  jail-bar,  and  safe  steel. 
Quite  often  when  there  are  but  two  layers  the  hard  one  can  be 
stripped  from  the  soft  one  by  placing  the  composite  in  a  vise 
and  driving  a  cold  chisel  between  the  layers.  The  hard  strip 
can  be  annealed  and  milled.  If  stripping  is  not  feasible,  then 
the  sample  should  be  annealed  and  the  hard  portion  drilled  with 
a  shallow,  diamond  pointed,  wide  drill  of  if  inch  diameter  at 
the  wings. 


DETERMINATION  OF   CARBON  IN  IRON  AND   STEEL      223 

If  it  is  desired  to  drill  a  hard  layer  between  two  soft  ones, 
the  whole  piece  can  be  heated  to  bright  redness  and  quenched  in 
water.  The  soft  layers  can  then  be  machined,  or  ground  off. 
The  hard  center  can  then  be  annealed  and  milled. 
_  It  is  a  little  more  difficult  to  obtain  drillings  or  millings  from 
a  soft  layer  lying  between  two  hard  ones.  In  such  a  case  the 
cross  section  of  the  steel  should  be  polished  fairly  smooth  and 
etched  with  1.20  nitric  acid  to  clearly  define  the  exact  depth  of 
the  layers.  The  higher  carbon  zones  will  be  plainly  marked  as 
black  bands  while  the  soft  steel  will  retain  its  natural  color. 
The  sample  is  annealed  before  the  etching  is  done,  so  that  one 
of  the  black  layers  can  be  machined  away.  The  white  layer  can 
then  be  drilled  with  a  wide,  flat  drill. 

In  general  it  is  a  good  thing  to  etch  the  polished  section  of 
samples,  as  often,  by  so  doing,  hard  layers  or  insertions  are 
discovered  when  least  suspected;  or  curious  defects,  or  spots 
or  streaks,  or  segregations  are  revealed. 

Test  for  Segregation: 

Segregated  steel  becomes  deeply  pitted,  in  the  segregated 
parts,  on  being  suspended  in  sufficient  i  :  10  sulphuric  acid  to 
maintain  a  continuous  evolution  of  hydrogen  for  several  hours. 
Polish  the  piece  fairly  bright  and  smooth  before  making  the 
test. 


CHAPTER  XI. 
PART  H. 

THE  DETERMINATION  OF  CARBON  IN  STEEL,  FERRO-ALLOYS, 

AND  PLUMBAGO  BY  MEANS  OF  AN  ELECTRIC 

COMBUSTION  FURNACE.* 

SEVERAL  months  ago  it  occurred  to  the  writer  that  a  special 
resistance  wire  could  be  applied  to  the  heating  of  combustion 
tubes.  A  drawing  was  prepared  for  a  furnace  of  a  muffle  type 
to  heat  four  tubes  lying  in  the  same  plane  and  parallel. 

After  some  correspondence  it  was  agreed  at  first  to  try  a  sin- 
gle tube  furnace.  It  consists  of  a  steel  tube  295  mm.  X  76.3  mm. 


FIG.  10. 

containing  a  non-conducting  packing  of  magnesia  oxide.  In 
the  center  is  a  quartz  {  tube  wound  with  the  patent  wire.  Inside 
of  this  tube  is  placed  another  of  the  same  material  of  19  mm. 

*  Reprinted  from  the  Journal  of  the  American  Chemical  Society  (with  addi- 
tions), Vol.  XXX,  No.  5,  May,  1908. 

t  In  place  of  jars  D  and  E,  the  shape  B,  Fig."  10,  is  used  which  has  a  wider 
neck  and  can  be  easily  cleaned  and  refilled.  That  is,  all  three  of  these  jars  are  the 
same  size  and  shape  as  B.  The  cut  on  page  233  and  the  photo  on  page  242  show 
how  this  can  be  done.  The  contents  of  the  respective  jars  are  the  same  as  before. 

t  The  author  now  uses  a  clay  tube  on  which  to  wind  the  wire.  He  also  is  now 
trying  wire  wound  directly  on  the  tapered  clay  combustion  tube. 

224 


DETERMINATION  OF  CARBON  IN   STEEL,  ETC.  225 

inside  diameter  and  600  mm.  long,  in  which  the  combustions 
are  made. 

A .  Mercury  pressure  gauge  for  detection  of  leaks  and  stoppages. 

B.  Jar  for  stick  potassium  hydroxide  or  for  any  solid  drier  or  absorbent. 

C.  Safety  jar  for  potassium  hydroxide  solution,  preventing  solution  from 

backing  over  into  rubber  tubing. 

D.  Calcium  chloride  jar. 

E.  Soda  lime  jar. 

F.  Mercury  valve,  to  prevent  reverse  action,  and  absorb  sulphur  coming 

from  rubber  tubing.    Note  blackening  of  mercury  after  a  time. 

G.  Electric  combustion  furnace. 
H.  Jar  for  granular  zinc  to  remove 

Acid  fumes, 

Litharge  fumes, 

Sulphur  fumes, 

Chlorine  fumes. 

7.    Jar  for  phosphoric  anhydride  to  remove  water. 
/.   Absorbent  and  weighing  apparatus  for  carbon  dioxide. 

The  writer  put  in  a  small  32  ohm  rheostat  that  happened  to 
be  at  hand.  With  about  ^  of  this  resistance  the  furnace,  on 
a  220  volt  direct  current,  has  been  maintaining  a  constant 
temperature.  To  secure  complete  combustion  of  steel  it  is 
very  essential  that  the  heat  be  maintained  as  close  to  950°  as 
possible,  i.e.,  as  little  under  that  temperature  as  practicable. 
If  the  temperature  drops  to  about  900°  or  under,  the  results 
obtained  are  liable  to  be  from  o.oi  to  o.io  per  cent  too  low, 
unless  red  lead  is  mixed  with  the  drillings.  Hence,  if  one  desires 
to  operate  with  oxygen  alone,  the  necessity  of  keeping  the  tem- 
perature from  940°  to  960°  Centigrade  cannot  be  made  too 
emphatic. 

The  oxygen  is  purified  by  passage  through  jars  of  stick  caustic 
potash,  potassium  hydroxide  solution,  calcium  chloride  and  soda 
lime  in  the  order  named.  The  oxygen  then  passes  through  a  mer- 
cury valve  into  the  porcelain  or  quartz  (fused  silica)  or  clay  tube, 
half  of  which  is  filled  loosely  with  ignited  asbestos.  The  prod- 
ucts of  the  combustion  are  purified  from  acid,  sulphur,  litharge 
or  chlorine  fumes  by  passing  through  a  jar  of  granulated  30 
mesh  zinc.  The  water  is  removed  by  a  jar  of  phosphoric  an- 
hydride. 


226  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

For  steels  containing  from  0.30  to  1.50  per  cent  carbon  2 
grams  of  fine  drillings,  not  over  -J  mm.  thick,  are  taken.  For 
still  lower  percentages  of  carbon  from  3.0  to  5.0  grams  of  drill- 
ings of  not  over  20  mesh  size  are  selected. 

The  sample  is  weighed  into  a  clay  boat.  The  steel  begins  to 
burn  by  the  time  the  stopper  of  the  combustion  tube  is  in  place. 
Two  grams  of  steel  are  decarbonized  in  3  minutes  and  5  grams 
in  6  minutes.  The  burning  is  continued  for  10  minutes  more 
with  oxygen  passing  through  the  combustion  tube  at  a  rapid 
rate.  The  weighing  apparatus  is  detached,  wiped  and  weighed. 
Twenty-five  minutes  afford  ample  time  for  a  single  combustion, 
counting  all  operations. 

The  weighing  apparatus  and  the  jars  for  the  purifying  train 
are  the  writer's  design,  and  were  first  published,  in  part,  with 
illustrations,  in  the  January  Journal  of  the  Engineers'  Society 
of  Western  Pennsylvania,  1906,  and  more  fully  in  the  Journal, 
Am.  Chem.  Soc.,  28,  862  (1906).  This  weighing  apparatus  / 
is  used  40  times  before  it  is  refilled.  As  it  is  always  weighed 
against  a  duplicate  for  a  tare,  after  the  fortieth  combustion  its 
tare  is  used  as  an  absorber  for  40  more  combustions,  so  that 
when  a  pair  has  been  freshly  filled  the  operator  knows  he  can 
complete  80  combustions  before  he  needs  to  refill  his  weigh- 
ing outfit.  Do  not  fill  /  quite  up  to  the  bend  of  the  inlet 
tube. 

While  no  red  lead  is  necessary  for  steel  combustions,  some  of 
the  alloys,  such  as  ferro-chrome,  carbonless  chrome,  and  ferro- 
boron,  require  that  red  lead  *  be  mixed  with  the  drillings  or 
powder  to  break  the  metallic  bond  and  permit  of  decarboniza- 
tion.  Ferro-chrome  is  the  most  refractory,  as  from  a  carbon 
content  of  more  than  4  per  cent  only  0.2  per  cent  was  obtained 
by  burning  as  in  steels  with  oxygen  alone,  at  a  temperature 
of  940°.  Pig  iron  also  requires  some  red  lead.  In  general, 
about  one-half  the  amount  of  lead  required  for  decarbonization 
in  a  gas  furnace  is  sufficient  for  the  same  work  in  the  electric 
furnace,  by  reason  of  the  higher  heat  attainable  within  the  range 

*  Or  litharge. 


DETERMINATION  OF   CARBON   IN   STEEL,   ETC. 


227 


of  durability.  A  few  of  the  many  comparisons  made  in  this  lab- 
oratory between  the  combustions  in  a  gas  furnace  with  red 
lead  and  oxygen  and  combustion  in  oxygen  alone  are  given  in 
Table  I: 


Sample. 

Method. 

Weight  of 
Drillings 
Taken. 

Amount  of 
Red  Lead 
Used. 

Per  cent 
Carbon 
Found. 

[o.      i  St 

eel                         

Electric 

Grams. 
4 

None 

O.OQ 

i 

Red  lead 

4 

7  grams 

0.09 

288 

Electric 

2 

None 

1  .176 

288 

Red  lead 

2 

4  grams 

1  .  175 

2 
2 

Electric 
Red  lead 

5 
4 

None 
7  grams 

0.  121 
O.  Ill 

2 

Electric 

if 

None 

0.976 

2 

Red  lead 

ii 

4  grams 

0.967 

Electric 

3 

None 

o.  109 

4 

Red  lead 

5 

7  grams 

0.118 

5 

Electric 

2 

None 

0.469 

5' 

Red  lead 

2 

4  grams 

0.474 

6 

Electric 

2 

None 

o.  736 

6 

Red  lead 

2 

4  grams 

o.  737 

7 

Electric 

2 

None 

0.118 

7 

Red  lead 

4 

7  grams 

0.117 

8 

Electric 

2 

None 

1.17 

8 

Red  lead 

2 

4  grams 

1.168 

Q 

Electric 

2 

None 

i   jr 

9 

Red  lead 

2 

4  grams 

1.16 

IO 

Electric 

r 

None 

o  046 

IO 

Red  lead 

4 

7  grams 

o  04.0 

The  advantages  of  the  electric  heating  apparatus  are  obvious. 
Very  little  heat  is  radiated ;  economy  of  space  is  attained;  tubes 
are  heated  gradually  and  cooled  gradually;  time  required  is 
the  minimum;  labor  cost  is  plainly  the  lowest  because  of  sim- 
plicity and  rapidity,  and  no  expensive  platinum  tubes  or  boats 
or  crucibles  are  used. 

Some  may  say,  "Why  not  burn  the  steel  in  air?"  The  an- 
swer is  that  the  cost  of  oxygen  is  small,  one-third  cent  per  com- 
bustion, and  the  steel  burns  twice  as  fast.  Oxygen  can  now  be 
had  at  if  cents  per  cubic  foot  in  100  cubic  foot  cylinders.  The 
method  is  accurate  for  all  steels.  As  pointed  out  in  the  writer's 


228  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

FERRO-ALLOYS  AND  PLUMBAGO. 


Sample. 

Method. 

Weight  of 
Drillings 
Taken. 

Amount  of 
Red  Lead 
Used. 

Per  cent 
Carbon 

Found. 

Tungsten  powder.  .  . 

Electric 

Grams. 

2 

None 

O.OO^ 

Plumbago,  No.  153 

Red  lead 
Electric 

2 

o  a 

4  grams 
None 

O.OIO 
50   700 

Plumbago,  No.  356 

Red  lead 
Electric 

O.2 
O    3 

4  grams 
None 

50  .  800 

^1   6  so 

Plumbago,  No.  i 

Red  lead 
Electric 

O.2 
O    2 

4  grams 
None 

51-300 

04  .  OOO 

68.5%  ferro-chrome  

Red  lead 
Electric 

o-3 
1  .0 

4  grams 
i  gram 

94.300 

4.  21 

Ferro-  vanadium,  No.  134  

Red  lead 
Electric 

1  .0 
1  .0 

4  grams 
None 

4.15 
3.12 

Ferro-titanium,  No.  i  

Red  lead 
Electric 

1  .0 

2.O 

4  grams 
None 

3-09 
O.  22 

Ferro-boron,  No.  i  

Red  lead 
Electric 

2.O 
.O 

4  grams 
i  gram 

O.24 

I  .73 

j  Carbonless  chrome,  No.  9  .... 
(  96  o%  chromium 

Red  lead 
Electric 
Red  lead 

.0 
.O 

o 

4  grams 
i  gram 
4  grams 

1.72 
0.08 
O   OO 

Pig  iron  

Electric 

.0 

None 

3.20 

"B" 

Electric 

o 

0.5  gram 

3.58 

Red  lead 

.0 

4  grams 

3.58 

article  and  in  his  preliminary  paper  read  before  the  Pittsburg 
Section  in  December,  1905,  one  may  lose  as  much  as  50  per 
cent  of  the  carbon  in  certain  alloy  steels  by  attempting  to  dis- 
solve the  borings  in  either  neutral  or  acid  double  chloride  of 
copper  and  potassium. 

The  best  protection  for  the  bottoms  of  clay  or  porcelain  boats 
is  a  liberal  layer  of  ignited  silica  sand,*  such  as  is  used  for  acid 
open-hearth  furnace  bottoms.  The  silica  rock  is  crushed  to 
about  2o-mesh  and  ignited  in  a  muffle  furnace  at  a  bright  red 
heat,  cooled,  and  kept  in  glass  stoppered  bottles.  Test  the  sand 
by  a  blank  analysis. 

To  secure  complete  decarbonization  it  is  necessary  either 
that  thin  drillings  be  used,  or  if  the  sample  contains  much  coarse 

*  Read  page  241  concerning  the  use  of  sand  in  combustion  boats. 


DETERMINATION  OF   CARBON  IN   STEEL,  ETC.  229 

or  bulky  material,  it  should  be  selected.  This  can  easily  be 
accomplished  by  pouring  the  borings  on  a  20  mesh  sieve  and 
shaking  all  of  the  steel  of  20  mesh  size  and  the  still  more  finely 
divided  dust  on  to  a  60  mesh  sieve,  which  retains  only  the  20 
to  60  mesh  material.  This  always  represents  a  good  average 
sample. 

Further,  the  drillings  should  be  placed  in  as  compact  a  mass 
as  possible.  If  curly  drillings  are  scattered  along  the  entire 
length  of  the  boat  instead  of  being  put  in  a  deep,  compact  body, 
borings  that  are  a  little  thick  will  frequently  be  found  to  still 
contain  unburned  metal.  This  detail  is  a  very  important  one. 
Of  course,  the  reason  is  that  drillings  lying  in  close  contact  heat 
each  other  to  incandescence  during  the  burning  with  oxygen. 

Also,  during  the  period  when  the  oxygen  is  being  absorbed  in 
large  quantity  by  the  burning  metal,  the  flow  of  the  gas  should 
be  regulated  so  that  there  is  an  excess.  That  is,  the  oxygen 
must  be  turned  on  in  sufficient  quantity  so  that  the  gas  is  bub- 
bling through  the  weighing  apparatus  slowly.*  However,  if 
the  gas  is  rushed  through  /  during  this  period  the  steel  becomes 
violently  heated  and  slags  with  the  sand  and  the  sides  of  the 
boat,  destroying  the  latter.  Worse  yet,  low  results  are  obtained 
frequently  in  this  way,  probably  due  to  the  formation  of  carbon 
monoxide,  which  is  driven  out  of  the  hot  portion  of  the  tube 
before  it  is  oxidized  to  the  dioxide. 

If  the  oxygen  is  turned  into  the  tubes  in  sufficient  quantity  to 
maintain  a  slow  stream  during  the  period  of  the  burning,  the  end 
point  of  the  combustion  is  distinctly  shown  by  a  sudden  increase 
of  the  speed  of  the  bubbling  through  /.  The  rush  of  oxygen 
is  then  checked,  but  the  rate  of  flow  is  still  rather  rapid  for  the 
final  10  minutes. 

The  weighing  apparatus  /  is  filled  not  quite  to  the  bend  of 
the  inlet  tube  with  a  solution  of  potassium  hydroxide  made  by 

*  In  order  to  maintain  the  slow  bubbling  through  /,  it  is  necessary  to  increase 
considerably  the  rate  at  which  the  oxgen  is  passing  through  C  during  actual 
burning  of  the  metal  to  oxide.  This  also  generates  the  required  white  heat  in  the 
steel  at  the  critical  time. 


230  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

dissolving  500  grams  of  the  latter  in  500  c.c.  of  water.  The 
drying  tube  at  the  outlet  of  /  is  closely  filled  with  pieces  of 
stick  caustic  potash  cracked  to  about  the  size  of  a  grain  of 
wheat.  To  prevent  the  caustic  potash  from  coming  in  contact 
with  the  small  rubber  stopper  in  the  drying  tube  a  loose  plug  of 
asbestos  is  placed  at  that  point.  The  little  bulb  of  this  drying 
tube  is  filled  about  half  full  of  glass  wool.  If  dry  sticks  of  caustic 
potash  are  cracked  quickly,  the  small  pieces  can  be  conveyed  to 
the  drying  tube  in  dry  condition  and  constitute  not  only  a  splen- 
did guard  against  loss  of  moisture  from  J  but  are  also  equally 
effective  as  an  absorbent  of  carbon  dioxide. 

If  a  porcelain  boat  is  used,  the  15  X  75  mm.  Royal  Meissen 
.boat  is  the  best  shape  and  most  durable  of  any  porcelain  boats 
that  the  writer  has  tried.*  When  putting  in  the  sand  bot- 
tom, fill  the  front  half  of  the  boat  about  f  full  and  then 
with  the  butt  end  of  the  forceps  make  a  trough  in  the  sand, 
working  it  well  up  the  sides  of  the  boat.  Pour  the  drillings 
from  the  weighing  bottle  into  this  depression.  By  so  doing  the 
drillings  are  kept  in  a  compact  mass,  and  when  the  combustion 
is  completed  the  burned  steel  can  be  lifted  out  in  a  small  cake. 
In  this  way  a  boat  can  be  used  from  10  to  15  times. 

When  a  great  many  combustions  are  made  daily,  the  fused 
silica,  or  electro  quartz,  tube  is  the  most  serviceable.!  The 
continuous  spraying  of  oxides  against  the  walls  of  a  porcelain 
tube  weakens  it,  and  when  the  current  is  turned  off  and  the  tube 
is  permitted  to  get  cold  the  contraction  causes  a  rupture.  Avoid 
spilling  steel  in  a  quartz  tube. 

To  prevent  the  contents  of  D,  B,  E  from  clogging  the  inlets 
and  outlets,  large  plugs  of  cotton  are  used  at  these  points.  Glass 
wool  plugs  should  be  used  in  H  and  loose  plugs  of  ignited  asbes- 
tos in  /.  Enough  mercury  is  placed  in  the  bottom  of  F  and  A 
to  form  a  seal.  The  inlet  end  of  the  quartz  tube  heats  some- 
what, and  it  is  better  to  wrap  it  several  times  around  with  a 

*  The  author  now  uses  vitrified  clay  boats  for  all  carbon  combustions, 
f  Read  page  232  concerning  the  vitrified  clay  combustion  tube  designed  by 
the  author. 


DETERMINATION  OF  CARBON  IN  STEEL,  ETC.     231 

strip  of  cheese-cloth,  the  end  of  which  dips  into  a  150  c.c.  beaker 
of  water  suspended  directly  underneath  by  means  of  copper 
wire.  During  the  absorption  of  carbon  dioxide  the  outlet  of  / 
is  protected  from  ingress  of  moisture  or  carbon  dioxide  or  fumes 
from  the  room  by  a  drying  tube  not  shown  in  the  figure.  It  is 
filled  with  pieces  of  stick  caustic  potash  broken  to  the  size  of  a 
pea. 

Oxygen  can  now  be  had,  under  high  pressure,  in  5o-foot  cylin- 
ders at  about  2  cents  per  cubic  foot,  and  in  ico-foot  containers 
at  about  if  cents  per  foot.  The  latter  quantity  will  supply  2 
furnaces,  night  and  day,  for  2  months. 

Gas  Combustion  Furnace  with  Blast.  The  gas  combustion 
furnace,  described  by  the  leading  supply  houses  as  "for  draft 
or  blast,  with  adjustable  flame  length  "  can  be  made  very  effec- 
tive where  compressed  air  is  at  hand.  The  author  modifies  it 
as  follows:  From  the  450  mm.  size  take  out  one  pair  of  tiles; 
shove  the  other  two  pair  together  into  the  middle  of  the  furnace 
frame.  Put  the  removed  tiles  on  top  of  the  remaining  four  to 
lessen  radiation  of  heat.  Close  all  of  the  burner  shutters  except 
the  four  middle  ones.  Let  the  inlet  end  of  the  f  inch  inside 
diameter,  30  inch  electro-quartz  tube  project  12  inches  beyond 
the  tiles,  and  the  outlet  end  6  inches  beyond  the  tiles.  Fill 
the  latter  end,  loosely,  with  ignited  asbestos  for  a  distance  of 
8  inches,  beginning  at  the  stopper.  Wrap  both  ends  at  the 
stoppers  with  wet  cheese-cloth  as  in  the  electric  furnace.  It  is 
essential  that  the  combustion  tube  be  at  least  30  inches  long, 
and  either  of  electro  quartz  or  platinum,  as  with  air  blast  and 
gas  the  furnace  will  heat  the  tube  to  from  1150°  to  1200°  C. 
in  20  minutes.  This  is  in  the  range  of  temperature  where 
it  is  possible  to  make  direct  combustions  with  air  passing 
through  the  combustion  tube  instead  of  oxygen.  Of  course 
such  a  furnace  is  noisy  and  radiates  quite  a  little  heat,  but  is 
inexpensive. 

In  addition  to  the  wet  wrappings,  with  such  extreme  heat,  it 
is  safer,  after  putting  in  the  charged  boat,  to  follow  it  with  a 
loose  plug  of  ignited  asbestos,  placed  in  the  tube  about  an  inch 


232  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

beyond  the  inlet  end.  This  protects  the  stopper  entirely  from 
radiated  heat.  This  plug  can  be  used  over  again. 

At  1000°  C.,  using  oxygen,  coarser  drillings  can  be  decarbon- 
ized than  at  950°  C.,  and  more  quickly.  Clay  boats  will  not 
stand  1100°  C.  They  crumble.  Porcelain  ones  flux  with  the 
steel.  Platinum  boats  are  necessary  at  1100°  C. 

When  making  combustions  with  air  instead  of  oxygen,  it  is 
advisable  to  pass  the  gases  formed  through  a  second  tube  filled 
with  copper  oxide  or  some  other  catalyzer  heated  to  redness.  Do 
not  put  oxide  of  copper  in  a  quartz  tube.  It  will  flux  it.  A 
f-inch  bore  R.  B.  porcelain  tube,  14  inches  long,  heated  by  a 
5-burner  Bunsen  combustion  furnace  answers  very  well.  With 
.such  a  catalyzer  direct  combustion  of  steel  drillings,  in  air,  is 
successful  at  about  1150°  C.  The  author  advises  against  com- 
bustions with  air  alone. 

Burn  heavy  chips  i  hour. 

THE  DIRECT  DETERMINATION  OF  CARBON  IN  STEEL, 

FERRO-ALLOYS  AND  GRAPHITE  BY  MEANS  OF  A 

COMPRESSED  AIR  AND  GAS  FURNACE. 

Compressed  air  should  be  considered  a  necessity  in  all  chem- 
ical laboratories,  however  small,  where  ignitions  of  any  kind  are 
part  of  the  daily  routine.  With  this  great  aid  to  combustion  the 
furnace  shown  in  the  illustration  (Fig.  n)  can  be  made  to  heat  a 
f-inch  bore  fused  silica  tube  to  from  1150°  to  1200°  C.  in  from  15 
to  20  minutes.  The  cut  shows  the  writer's  modification  of  the 
original  arrangement  of  the  tiles.  One  pair  of  the  latter  is  re- 
moved from  a  *  495  mm.  furnace;  the  other  two  pair  are  shoved 
together  into  the  middle  of  the  furnace.  The  removed  tiles 
are  placed  on  top  of  the  middle  pair  forming  an  arch  at  P,  P. 

The  vacant  spaces  at  either  end  of  the  frame  are  packed  with 

asbestos  wool.     All  of  the  burner  shutters  are  kept  closed  except 

the  four  middle  ones  at  0.    To  permit  the  flame  to  pass  up  freely, 

the  tiles  are  separated  about  f  inch  at  the  bottom,  Mff,  M"f 

*  No.  17  furnace,  18  inches  long. 


DETERMINATION  OF   CARBON  IN   STEEL,   ETC.  233 

and  J  inch  at  the  top,  Mt  M'  (Fig.  n).  This  is  easily  accom- 
plished by  sliding  \  the  iron  frame  up  the  inclined  iron 
supports.  One  can  readily  adjust  the  air  pressure  and  the  gas 
at  the  points  indicated  to  produce  950°  C.  in  ten  minutes.  The 


FIG.  ii. 

Showing  the  Fletcher  Tube  Furnace  as  modified  by  Charles  Morris  Johnson  and  fitted 
with  his  combustion  train. 


range  between  950°  and  1000°  is  best  for  the  work.  To  provide 
for  variations  of  air  pressure  a  small  regulator  is  located  at  R. 
This  regulator  is  inexpensive  and  can  be  bought  from  any  con- 
cern supplying  pressure  faucets. 

To  prevent  the  cracking  of  the  fused  silica  (electro-quartz) 
tubes  when  using  this  furnace  for  the  determination  of  carbon 
in  steel  by  the  direct  combustion  of  the  drillings  in  oxygen,  a 
small  inner  sleeve  or  tube  of  platinum  should,  by  all  means,  be 
at  hand.  If  the  quartz  combustion  tube  be  heated  much  above 
950°  C.  and  a  single  drilling  is  spilled  in  it,  or  the  highly  heated 
steel  cuts  through  the  clay  or  porcelain  boat,  the  oxide  of  iron 
forms  slag  with  the  silica  of  the  tube  and  the  latter  will  soon 
crack.  To  avoid  frequent  and  expensive  breakage  of  combus- 
tion tubes  from  this  cause  the  writer,  in  1906,  designed  the 
small  cylinder  of  platinum  shown  at  Q,  Q'  (Fig.  n).  Q  shows 
the  open  end  of  the  same  and  Qf  gives  a  view  of  the  closed  end 
of  the  cylinder.  One-half  of  this  end  is  perforated  with  small 
holes.  It  is  125  mm.  long  and  18  mm.  in  diameter.  It  can  be 
made  to  weigh  not  over  30  grams  and  at  a  cost  of  about  $28.00.* 
The  cylinder  is  kept  in  the  combustion  tube.  To  receive  the 
*  The  present  high  price  of  platinum  makes  this  cylinder  undesirable. 


234  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

charged  boat  and  for  the  removal  of  burnt  residues  this  holder 
is  drawn  nearly  but  not  quite  to  the  entrance  of  the  quartz  tube. 
Keep  it  just  a  little  back  of  the  stopper.  The  clay  boat  into 
which  the  steel  drillings  are  poured,  in  a  little  pile,  is  slipped 
into  the  cylinder  and  the  combination  is  quickly  pushed  into 
the  hottest  part  of  the  combustion  tube.  The  tube  is  stoppered 
as  rapidly  as  possible  and  oxygen  is  immediately  turned  in  with 
sufficient  volume  to  maintain  a  medium  rate  of  bubbling  through 
the  absorbing  and  weighing  apparatus  /.  As  soon  as  the  steel 
gets  heated,  it  begins  to  absorb  oxygen  in  large  quantities  as 
shown  by  the  slackening  of  the  rate  of  bubbling  through  /.  It 
is  highly  important  to  continue  to  turn  in  more  of  the  gas  so  as 
to  always  maintain  an  excess  of  it  or  low  results  will  be  obtained. 
Increase  the  flow  of  the  oxygen  through  C  so  as  to  keep  up  a 
fairly  rapid  stream  of  gas  passing  through  /  during  the  absorp- 
tion period.  When  the  burning  is  completed,  which  occurs  in 
about  5  minutes  after  the  tube  has  been  stoppered,  the  oxygen 
will  begin  to  rush  through  J  at  a  high  rate  of  speed.  The  flow 
is  now  checked  to  the  normal  which  is  still  quite  rapid  as  but 
10  minutes  more  are  allowed  to  complete  the  combustion  of  2 
grams  of  steel  and  carry  all  of  the  CQz  over  into  the  weigh- 
ing apparatus  /  (Fig.  n).  Allowing  2  minutes  for  the  final 
weighing,  an  accurate  combustion  of  steel  drillings  can  be  made 
in  from  20  to  22  minutes.  The  writer  operates  furnaces  in  pairs 
by  a  2-way  connection.  This  still  further  reduces  the  average 
time  per  combustion,  counting  all  operations  except  the  drilling 
of  the  sample. 

The  second  furnace  is  placed  parallel  with  the  one  shown  in 
the  cut.  The  air  pressure  for  this  extra  furnace  is  bled  from  a 
cock  on  the  furnace,  shown  at  A  (Fig.  12).  It  is  the  middle  one 
which  is  closed  in  the  illustration  (Fig.  n).  The  air  is  conducted 
from  this  point  to  the  same  cock  on  the  additional  furnace  by 
heavy  pressure  tubing.  In  this  way  air  for  2  furnaces  can  be 
supplied  from  one  regulator  at  R.  By  similar  means,  through 
a  Y  not  given,  gas  can  be  furnished  from  the  i  gas  nipple 
located  near  R. 


DETERMINATION  OF   CARBON  IN  STEEL,  ETC. 


235 


The  oxygen  is  turned  in  at  oxy.  (Fig.  n)  and  is  distributed  at 
the  first  Y  to  the  pressure  gauge  at  A  which  contains  a  little 
mercury.  It  serves  the  2-fold  purpose  of  indicating  stoppages 
and  leaks.  If  there  be  a  stoppage,  the  mercury  will  rise  to  an 
abnormal  height  in  the  tube  that 
dips  under  the  mercury  in  A  .*  To 
test  for  leaks,  plug  with  a  glass  rod 
the  outlet  end  of  the  purifying  train 
at  the  point  where  the  absorption 
and  weighing  apparatus  /  is  shown 
attached.  Then  turn  on  the  oxy- 
gen until  the  mercury  rises  in  A  to 
the  first  bend  of  its  outlet  tube. 
Then  shut  off  the  oxygen:  If  there 
be  a  leak  beyond  C  in  the  direc- 
tion of  the  furnace,  the  mercury 
will  slowly  drop  and  the  slightly 
compressed  oxygen  will  bubble 
very  slowly  through  C,  if  the  leak 
be  a  small  one.  But,  if  the  leak  be  somewhere  between  C 
and  the  oxygen  tank  in  the  direction  BS'S,  then  instead  of 
there  being  a  bubbling  through  C,  the  fluid  in  the  latter  will 
recede  from  the  bottom  of  C,  rising  up  into  the  side  bulb 
of  C.  The  valves  on  oxygen  tanks  frequently  develop  leaks 
and  the  little  gauge  at  once  calls  attention  to  the  fact  if  this 
test  is  made.  C  is  filled  to  the  distance  shown  in  the  drawing 
with  a  solution  consisting  of  250  grams  of  caustic  potash  dis- 
solved in  250  c.c.  of  distilled  water.  The  oxygen,  after  passing 
the  first  F,  enters  B  via  the  glass  tube  SS.  It  then  passes  down 
through  B  (Fig.  n)  which  has  a  loose  plug  of  cotton  at  the  top 
and  is  filled  with  short  pieces  of  stick  caustic  potash.  The  gas 
leaves  B  at  the  bottom  outlet  and  enters  C  via  the  S-shaped  glass 
tube.  The  gas  bubbles  through  the  fluid  in  C  and  enters  D  at 

*  When  2  furnaces  are  in  operation  the  required  pressure  in  A  will  cause 
the  mercury  in  it  to  rise  to  a  height  of  about  35  mm.  It  is  a  great  advantage 
to  have  2  furnaces.  One  checks  the  results  obtained  in  the  other. 


FIG.  12. 

No.  17  Furnace  open  ready  for  the  intro- 
duction of  a  tube. 


236  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

the  top  where  there  is  a  loose  wad  of  cotton.  D  is  filled  with 
alternate  layers  of  anhydrous  calcium  chloride  and  cotton. 
The  gas  leaves  D  at  the  bottom  outlet  and  enters  E  at  its  bottom 
inlet.  E  is  filled  with  alternate  layers  of  cotton  and  soda-lime. 
The  bottoms  of  the  jars  are  filled  with  loose  plugs  of  cotton  to 
prevent  the  clogging  of  inlets  and  outlets  by  these  salts.  The 
oxygen  travels  up  through  E  and,  by  way  of  a  glass  tube,  can 
be  distributed  to  the  pair  of  combustion  furnaces  at  the  second 
Y  tube. 

The  combustion  tube  is  of  fused  silica,  or  electro-quartz.  It  is 
30  inches  long  and  projects  12  inches  beyond  the  furnace  frame  at 
the  inlet  end  and  6  inches  beyond  the  frame  at  the  outlet  end. 
It  is  filled  loosely  with  ignited  asbestos  for  a  distance  of  8  inches 
beginning  at  the  outlet  end.  Both  ends  of  the  tube  are  wrapped 
at  the  stoppers  with  wet  cheese-cloth,  the  ends  of  which  dip  into 
beakers  filled  with  water  as  shown  at  N,  N'.  The  products  of 
the  combustion  are  purified  from  litharge,  sulphur,  chlorine  and 
acid  fumes  by  a  jar  of  granulated  zinc  of  20  mesh  fineness  (H) . 
The  gases  are  further  dried  by  passing  up  through  a  jar  of  P20s 
powder  (i).  "i"  has  a  loose  plug  of  ignited  asbestos  at  the 
bottom  of  it  and  a  similar  one  at  the  top.  The  pure  CO2  is 
now  received  into  the  weighing  apparatus  J  which  is  filled  with 
the  same  kind  of  solution  as  given  for  C,  halfway  to  the  bend  of 
the  tube  that  dips  into  it.  The  guard  tube  L  is  filled  with  small 
pieces  of  dry  caustic  potash  prepared  by  quickly  breaking  the 
dry  sticks  in  a  porcelain  mortar  to  about  the  size  of  large  grains 
of  wheat.*  Reject  the  dust  and  use  it  for  the  absorbing  solution. 
Such  a  tube  makes  a  most  effective  guard  against  loss  of  moisture 
from  /  and  also  acts  as  a  further  absorbent  of  CCV  This  ap- 
paratus J-L  is  good  for  40  ordinary  steel  combustions  at  a 
rapid  speed.  It  is  weighed  against  a  mate  and  thus  80  com- 
bustions are  obtained  from  a  pair  before  refilling  is  necessary. 
D,  B,  E,  I  and  H  are  refilled  by  removing  the  glass  goose  necks. 
The  tube  K  is  filled  with  the  same  material  as  L  and  prevents 

*  The  bulb  of  L  is  filled  with  glass  wool.  The  little  rubber  stopper  is  pro- 
tected from  the  pieces  of  KOH  by  a  loose  wad  of  ignited  asbestos. 


DETERMINATION  OF   CARBON  IN  STEEL,   ETC.  237 

any  suction  of  impure  air  into  the  weighing  apparatus  during 
the  process  of  a  combustion.  The  writer  designed  the  entire 
train  several  years  ago  with  a  view  to  reducing  the  use  of  rubber 
stoppers  to  a  minimum  and  to  provide  a  convenient  form  of 
weighing  apparatus  for  carbon  dioxide.  When  using  J-L  for  the 
determination  of  carbon  in  plumbago  (natural  graphite)  it  is 
replenished  when  3  grams  of  C02  have  been  absorbed. 

It  is  important  that  the  small  tube  that  dips  into  the  KOH  so- 
lution in  L-J  be  not  less  than  6  mm.  outside  diameter  and  that 
its  internal  diameter  be  not  reduced  as  it  is  very  necessary  for 
rapid  work  that  it  deliver  large  bubbles  to  the  absorbing  fluid. 

In  ordering  quartz  or  fused  silica  tubes  the  chemist  should 
specify  that  the  ends  be  fused  smooth,  free  from  inside  chipping 
and  grooves,  and  of  practically  round  bore,  otherwise  he  may 
have  unpleasant  experiences  with  leaks  at  stoppers.  He  should 
further  insist  that  the  tubes  be  of  full  f  inches  inner  diameter 
for  at  least  J  of  the  length,  or  his  small  platinum  cylinder  may 
stick  in  the  tube. 

Care  should  be  taken  to  keep  the  heat  of  the  furnace  very  little 
in  excess  of  1000°  C.  as  combustion  with  oxygen  at  higher 
heats  will  cause  the  drillings  to  flux  with  the  boat,  cut  through 
the  latter,  and  at  times  stick  to  the  platinum  sleeve.  The 
operator  will  soon  learn  to  judge  the  proper  heat  without  a 
pyrometer:  If  on  drawing  out  the  boat  he  finds  nothing  in  it 
but  a  fused  slag  and  that,  perhaps,  the  latter  has  cut  through 
the  boat,  then  he  has  been  working  at  a  temperature  in  excess 
of  1000°  C.  If  he  finds  a  residue  that  is  a  dull  black  mass 
of  oxide  which  can  be  broken  off  short  in  his  fingers,  does  not 
present  more  than  a  slight  melted  appearance  on  top  and  does 
not  contain  particles  of  unburned  steel,  then  the  temperature 
of  the  furnace  is  just  right.  If  the  residue  instead  of  being  of 
a  dull  lustrous  jet  black  has  a  slightly  reddish  appearance,  the 
combustion  has  been  made  at  too  low  a  heat  and  the  decarboni- 
zation  is  incomplete.  If  the  combustion  tube  presents  a  white 
hot  appearance,  inside,  the  heat  has  attained  to  1200°  C.  If 
the  heat  has  a  dazzling  effect  the  temperature  is  still  higher. 


238  CHEMICAL  ANALYSIS  OF   SPECIAL   STEELS 

A  yellow  heat,  viewed  in  the  bright  daylight,  is  about  920°  to 
980°  C.;  a  bright  yellow,  suggesting  the  first  appearance  of 
whiteness,  is  about  1150°  C.  By  exercising  a  little  care  in 
adjusting  the  air  and  gas  supply  this  furnace  can  be  operated 
with  very  little  noise  or  radiation  of  heat  and  yet  develop 
from  950°  to  1000°  C.,  which  is  ample  for  direct  combustion 
of  steel  in  oxygen.  A  small  milling  attachment  should  be  on 
every  drill  table,  such  as  is  used  in  " gumming"  saws.  In 
this  way  finely  divided  millings  can  be  obtained  from  thin 
sheets,  wire  and  razor  blades.  The  writer  uses  |  pitch  cutters 
that  ar£  held  in  a  chuck  in  the  same  manner  as  a  drill.  The 
sheet  or  wire  is  clamped  to  the  drill  table  and  is  shoved  against 
the  milling  cutter  which  is  revolving  horizontally.  The  writer 
now  uses  his  milling  machine  (see  page  220,  Fig.  9). 

The  drillings  or  millings,  which  should  be  either  very  thin, 
medium  size,  curly  ones  or  should  pass  a  20  mesh  sieve  if  from 
soft  or  annealed  steel,  are  put  in  the  boat  in  as  compact  a  mass 
as  possible.  The  drillings  should  not  be  scattered.  Do  not 
try  to  remove  the  residue  after  a  combustion.  Put  in  the  next 
sample  in  a  little  pile  and  as  close  as  possible  to  the  oxide  re- 
maining from  a  previous  analysis.  In  this  way  from  4  to  5 
carbon  determinations  can  be  made  in  a  clay  boat  without 
bothering  with  a  sand  bottom.  Of  course  porcelain  boats  can 
be  used  for  this  work  but  they  are  more  expensive  and  do  not 
last  any  longer  than  a  well  made  clay  boat.  Sand  should  be 
used  to  protect  the  bottoms  of  the  porcelain  boats.  Well  ignited 
silica  sand,  such  as  is  used  in  furnace  bottoms,  is  suitable.  As 
stated  the  writer  has  found  that,  with  a  little  practice  in  manip- 
ulation of  the  gas  and  air  pressure,  the  furnace  shown  in  the 
cut  can  be  made  to  heat  to  from  1000°  to  1050°  C.  with  very  little 
noise  and  radiation  of  heat.  On  the  other  hand  it  can  be  run 
with  much  unnecessary  racket.  In  this  laboratory  natural  gas 
is  used  at  a  pressure  of  8  ounces.  A  moderate  air  pressure  is 
sufficient,  i.e.,  about  30  pounds. 

When  making  direct  carbon  combustions  of  pig  iron  in  oxygen, 
shake  up  with  the  1  gram  of  sample  half  this  amount  of  red 


DETERMINATION  OF   CARBON  IN  STEEL,   ETC.  239 

lead  or  litharge  to  break  the  bond  between  the  iron  and  silicon. 
This  secures  complete  combustion  of  pig  iron.  For  refractory 
substances  like  ferro-chrome,  carbonless  chrome,  silicon  carbide, 
metallic  silicon  and  ferro-boron,  weigh  i  gram  of  sample  and 
mix  the  same  with  4  grams  of  litharge.  Put  this  charge  in  a 
clay  boat  and  proceed  with  the  combustion  as  given  for  steels. 
Deduct  a  blank  due  to  the  CO2  obtained  from  the  lead  oxide. 
It  is  safer  to  follow  this  plan  for  tungsten  and  molybdenum 
powders,  ferro-silicon,  ferro-vanadium,  ferro-titanium  and 
ferro-molybdenum.  All  varieties  of  plumbago  or  natural 
graphite  that  the  writer  has  analyzed  in  connection  with  the 
plumbago  crucible  factory  of  this  works,  when  finely  ground  as 
described  in  his  methods  for  the  analysis  of  graphite,  burn  com- 
pletely to  CO2  in  oxygen.  Some  of  the  finer  grades  of  the 
natural  concentrated  product  yield  99  per  cent  pure  carbon. 
It  requires  about  45  minutes  to  completely  burn  such  material. 

When  using  red  lead  or  litharge  to  secure  complete  combustion 
of  the  carbon  in  ferro-alloys  rich  in  aluminum  or  silicon,  or  both, 
the  charge  is  placed  in  one  end  of  the  clay  boat  without  a  sand 
bottom.  After  completing  the  combustion  which  proceeds 
just  as  quickly  as  that  of  a  steel  with  oxygen,  alone,  the  used 
part  of  the  boat  is  broken  off  and  the  other  half  is  then  taken  for 
further  combustions.  The  best  way  to  determine  the  blank, 
due  to  the  lead  oxide,  is  to  burn  2  or  4  grams  of  it  with  some 
20  to  30  mesh  siftings  of  a  steel,  the  carbon  content  of  which  is 
accurately  known;  or  with  2  grams  of  small  thin  curly  drillings 
of  some  standard  steel.  The  excess  of  carbon  found  is  the  blank 
due  to  the  lead  oxide.  A  good  "  C.  P."  or  commercial  red  lead  or 
litharge  will  give  a  blank  of  about  0.004  gram  of  CC>2  per  4 
grams  of  lead  oxide. 

L-J  is  wiped  off  with  a  piece  of  clean  cheese-cloth  or  a  clean 
handkerchief  before  each  weighing  of  it.  Its  outlet  and  inlet 
ends  are  kept  closed  with  small  rubber  caps  when  it  is  not  con- 
nected in  the  train.  These  caps  are  removed  during  weighings. 
Not  more  than  2  minutes  are  spent  in  weighings  at  the  end  of 
the  combustion.  One  minute  is  sufficient  to  weigh  the  drillings 


240  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

at  the  start  One  or  two  minutes  more  may  be  consumed  in 
transferring  the  boat  to  the  combustion  tube  and  connecting 
L-J  in  the  train.  But  15  minutes  are  required  to  burn  the 
sample  and  carry  all  of  the  CO?  to  L-J.  In  this  way  perfectly 
accurate  combustions  of  all  kinds  of  steels,  either  plain  or  alloyed, 
with  any  amount  of  tungsten,  molybdenum  or  chromium  can 
be  carried  through  in  20  minutes.  This  is  the  routine  practice 
in  this  laboratory  when  making  bath  tests  of  open  hearth  heats 
before  same  are  ready  for  tapping. 

This  furnace  has  one  marked  advantage  over  electrically 
heated  furnaces,  in  that  it  can  be  brought  from  a  cold  state  to 
1000°  C.  in.  10  minutes.  It  can  also  be  adjusted  to  fit  any  size 
combustion  tube.  (See  Fig.  12.) 


CHAPTER  XL 
PART  III. 

FURTHER  NOTE  ON  THE  DETERMINATION   OF   CARBON  IN 
STEEL  AND   FERRO-ALLOYS. 

SURFACE  DECARBONIZATION. 

REFERRING  to  remarks  on  page  218  relative  to  the  taking  of 
samples  it  must  be  noted  that  steel  often  has  a  decarbonized  sur- 
face, that  is  from  10  per  cent  to  almost  any  amount  lower  in  car- 
bon than  the  main  body  of  the  metal.  This  will  often  cause  the 
chemist  to  report  the  rolled  or  hammered  steel  anywhere  from 
o.io  to  0.20  lower  in  carbon  than  the  original  ingot  analysis, 
that  is,  suppose  the  ingot  analysis  was  1.20  per  cent  carbon 
then  it  not  infrequently  happens  that  the  plate  or  bar  may  show 
but  1. 10  per  cent. 

USE  OF  SAND  IN  BOATS. 

The  author  no  longer  uses  any  sand  in  the  combustion  boat 
as  the  composite  vitrified  clay  boat  is  greatly  superior  and  with- 
stands a  much  higher  heat  than  the  original  form  of  clay  boat. 
By  avoiding  extreme  heats  during  the  combustion,  complete 
decarbonization  can  be  effected  without  fusing  the  drillings 
to  the  boat,  and  the  little  pile  of  sintered  oxide  that  remains 
after  the  burning  can  be  scraped  out  with  the  tail  of  a  small  file. 
If  the  combustions  are  run  at  a  high  heat  with  the  drillings  in 
contact  with  a  sand  bottom  there  is  danger  of  forming  silicon 
carbide  as  has  been  pointed  out  by  Mr.  Geo.  M.  Berry. 

OXYGEN  VERSUS  AIR  IN  DIRECT  COMBUSTION. 

Since  writing  the  first  edition  of  this  book  the  price  of  oxygen 
has  fallen  to  less  than  2  cents  per  cubic  foot  so  that  there  is  no 
longer  any  inducement  to  try  direct  combustions  in  air.  In 

241 


242 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


DETERMINATION  OF    CARBON   IN   STEEL,   ETC.  243 

any  case  the  high  temperatures  necessary  make  such  combustions 
very  unpleasant  and  should  be  avoided. 

Two  PARALLEL  FURNACES. 

Photo  No.  13  shows  the  author's  arrangement  for  two  com- 
bustion furnaces,  side  by  side. 

THE  GAS  COMBUSTION  FURNACE  WITH  BLAST. 

On  page  233  the  above  direct  combustion  method  is  referred 
to.  It  constitutes  a  very  cheap  and  effective  way  of  making 
direct  combustions.  The  principal  objection  to  this  method 
of  heating  is  that  the  sharp,  bare  flame  of  the  compressed  air 
furnace  striking  the  fused  silica  tube  causes  the  latter  to  become 
devitrified  and  leak  after  some  time. 

THE  ELIMINATION  OF  RUBBER  STOPPERS  FROM  THE  VITRI- 
FIED CLAY  COMBUSTION  TUBE  BY  MEANS  OF  TA- 
PERED CLAY  INLET  AND  OUTLET. 

Received  June  13,  1913. 

BY   CHAS.    MORRIS   JOHNSON. 

IN  this  journal,  5,  488,  the  writer  published  an  account  of  a 
vitrified  clay  combustion  tube  with  tapered  outlet  designed  by 
the  author  and  manufactured  at  this  works.  The  tube  has  been 
in  successful  operation  for  6  months  of  24  hour  working  days  and 
is  still  in  commission.  Several  more  are  now  in  use  and  mark 
a  considerable  reduction  in  cost  of  carbon  determinations  as  the 
material  from  which  the  tubes  are  made  costs  less  than  i  cent 
per  tube. 

The  advantage  of  the  tapered  outlet  very  soon  suggested  the 
making  of  a  tapered  clay  inlet  which  is  shown  at  K  in  the  illus- 
tration and  also  at  L-M.  (Fig.  14.) 

The  clay  part  of  the  inlet  is  a  duplicate  of  the  outlet  end.  The 
tube  is  charged  and  discharged  by  removing  L-M  which  is  con- 
nected to  the  main  part  of  the  combustion  tube  by  means  of 
the  rubber  sleeve  M .  This  connection  is  a  piece  of  f  inch  bore, 


244  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


DETERMINATION  OF  CARBON  IN  STEEL,  ETC.     245 

T3F  inch  wall  and  2\  inches  long,  pure  rubber  tubing.  This 
sleeve  is  more  easily  handled  than  a  rubber  stopper.  The  oper- 
ator grasps  L-M  at  the  clay  part  L  and  slips  it  over  the  main 
part  of  the  combustion  tube  and  twists  it  firmly  in  place.  The 
clay  part  L  offers  a  substantial  hold  for  one's  hand  and  is  abso- 
lutely safe.  A  glass  taper  would  be  dangerous  as  it  might  be 
crushed  when  grasped,  causing  a  wound. 

The  slip-over  connection  is  geometrically  a  tighter  connection 
than  a  rubber  stopper,  for  the  reason  that  the  latter  affords  an 
example  of  a  conical  surface  pierced  by  the  cylindrical  surface 
of  the  combustion  tube  which  makes  only  a  single  circle  of  con- 
tact between  the  stopper  and  the  tube.  The  slip-over  gives  a. 
tangential  contact  which  provides  innumerable  circles  of  contact. 

Further  superiority  of  the  tapered  clay  and  rubber  sleeve: 
inlet  is  that,  should  the  bore  of  the  combustion  tube  tend  to  be 
elliptical  instead  of  a  true  circle,  the  elasticity  of  the  rubber 
sleeve  will  still  give  a  pressure  tight  connection  on  account  of 
the  large  surface  of  contact. 

Again,  many  combustion  tubes  offered  by  dealers  are  rejected 
because  of  grooves  in  the  interior  walls,  at  the  inlet  or  outlet 
ends,  which  make  tight  connections  with  rubber  stoppers  im- 
possible. The  tapered  slip-over  connection  renders  such  tubes 
perfectly  satisfactory. 

The  entire  apparatus  with  the  single  exception  of  the  little 
mercury  valve  tube  attached  to  L-M  is  the  author's  design  and 
shows  but  one  rubber  stopper  at  an  unimportant  point  in  the 
little  KOH  drying  tube  at  the  extreme  outlet  end  of  the  combus- 
tion train.  This  could  also  be  eliminated  by  a  small  glass  taper 
or  clay  taper.  The  wet  wrapping  can  be  omitted,  entirely, 
when  the  clay  tube  is  used,  although  shown  in  Fig.  14. 

It  has  been  found  in  the  author's  experiments  that,  for  a  given 
wiring,  furnaces  heat  higher  with  clay  tubes  than  when  fused 
silica  tubes  are  used  as  there  is  less  leakage  of  heat  via  the  tube 
when  the  clay  tube  is  in  the  furnace. 


CHAPTER  XI. 

PART  IV. 

THE    DETERMINATION    OF    CARBON   IN   PLAIN    STEEL    AND    IN 

ALLOY  STEELS,   CONTAINING   NOT   OVER  ONE  OR  TWO 

PER  CENT  OF  ALLOYS,  BY  SOLUTION  IN  COPPER 

AND  POTASSIUM  CHLORIDE. 

THE  limitations  of  this  method  cannot  be  absolutely  fixed 
•as  the  carbon  can  be  accurately  obtained  on  certain  alloys  that 
have  a  greater  amount  of  the  non-ferrous  metals  than  given  in 
the  above  title;  notably  nickel  steels  can  be  accurately  deter- 
mined for  carbon  where  the  nickel  content  is  far  in  excess  of 
2  per  cent.  The  reader  should  refer  in  this  connection  to  pages 
203  to  207.  Occasionally  the  chemist  receives  thick  chips 
that  are  impossible  by  the  method  given  on  the  pages  just 
mentioned,  and  rather  than  wait  for  a  more  suitable  sample  or 
perhaps  put  a  good  customer  to  the  inconvenience  of  getting 
drillings  of  the  proper  fineness,  the  analyst  will  resort  to  the 
double  chloride  method.  The  details  are  as  follows: 

THE  DISSOLVING  SOLUTION. 

The  acid  solution  given  on  page  204  is  used  for  this  work.  It 
is  filtered  on  ignited  asbestos.  The  latter  is  prepared  by  ignit- 
ing the  fine  white  fiber  in  a  muffle  furnace  in  a  porcelain  dish. 
The  dish  is  filled  heaping  full  and  brought  to  a  bright  red;  it  is 
then  removed  from  the  furnace  and  allowed  to  cool  below  red- 
ness. The  lump  of  partially  ignited  asbestos  is  turned  over 
and  the  dish  and  its  contents  are  returned  to  the  furnace; 
again  brought  to  bright  redness;  and  so  on  until  the  asbestos 
has  been  heated  and  cooled  three  times.  While  the  asbestos 
is  cooling  it  should  be  covered  with  a  clean  agate  ware  pan  to 
prevent  soot  or  carbonaceous  dirt  of  any  kind  from  falling  on 

246 


CARBON  IN  PLAIN   STEEL  AND   ALLOY   STEELS 


247 


the  asbestos.  The  ignited  asbestos  is  cut  into  short  wads;  put 
into  a  glass  stoppered,  carefully  cleaned  quart  bottle  and  enough 
distilled  water  mixed  with  it  to  make  a  rather  thick  pulp. 

The  pulp  is  poured  on  a  perforated  porcelain  plate  of  at  least 
2  inches  diameter  which  is  kept  from  slipping  out  of  level  by 
applying  slight  suction  while  the  filter  is  being  prepared.  The 
asbestos  is  distributed  over  the  plate  in  an  even  layer  about  i 


PHOTO  No.  15. 

inch  thick  and  is  put  firmly  to  place  by  increasing  the  suction  a 
little  and  pressing  it  down  with  a  glass  rod.  (One  end  of  the  rod 
is  flattened  into  a  disk  by  softening  it  in  the  flame  of  a  Bunsen 
burner  and  quickly  pressing  it  against  a  cold  surface.)  Repeat 
this  operation,  adding,  in  the  same  way,  successive  layers,  taking 
care  not  to  tamp  the  latter  too  much  as  by  so  doing  the  filtration 
will  be  very  slow  and  will  require  excessive  suction  to  get  the 
solution  through  the  filter  at  all.  When  the  layers  have  at- 
tained a  total  thickness  of  about  an  inch  and  one-half  the  whole 
filter  is  saturated  several  times  with  i  :  i  HC1  to  shrink  it  tighter; 


248 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


it  is  tamped  some  more,  and  then  washed  ten  times  with  dis- 
tilled water.  The  glass  filter  *  tube  in  which  the  filter  is  made  is 
shown  in  photo  No.  15.  The  filter  being  now  ready  is  trans- 
ferred, rubber  stopper  and  all,  to  the  bottle  in  which  the  solu- 
tion to  be  filtered  is  to  be  kept.  The  photo 
shows  a  glass  filter  tube,  but  usually  a  carbon 
filter  tube  is  too  small  for  filtering  the  whole  solu- 
tion so  that  the  filter  layer  is  prepared  on  the 
porcelain  plate  supported  in  a  large  funnel  that 
pierces  a  rubber  stopper  that  will  fit  the  neck 
both  of  the  side  neck  suction  flask  shown  and  of 
the  large  glass  stoppered  bottle  in  which  the 
filtered  solution  is  to  be  preserved.  The  double 
chloride  is  then  filtered  into  the  latter  bottle  with 
moderate  suction;  kept  stoppered;  and,  to  pre- 
vent dust  from  settling  around  the  stopper,  a  cap 
of  stout  paper  is  tied  over  the  same.  The  photo 
No.  15  shows  the  brass  water  pump  used  which 
is  extremely  satisfactory  and  inexpensive.  It  discharges  into  a 
deep  stone  box  as  shown.  Cut  A  illustrates  the  details  of  the 
brass  pump. 

SOLUTION  OF  THE  CHIPS  AND  FILTERING  OUT  OF  THE 
CARBON. 

Dissolve  from  i  to  5  grams  of  the  chips  in  60  c.c.  of  the 
double  chloride  per  gram  of  sample  in  a  beaker  that  has  been 
cleaned  from  all  lint  or  dust.  The  chips  must  be  stirred  at 
intervals  with  a  glass  rod  until  there  no  longer  remains  on  the 
bottom  of  the  beaker  any  particles  of  copper  coated  steel.  The 
reactions  occurring  are  given  herewith  for  the  benefit  of  the 
student:  In  the  first  place  the  iron  is  dissolved  away  from 
the  carbon  by  reaction  (i),  Fe  +  CuCl2  =  FeCl2  +  Cu;  then 
a  further  portion  of  the  copper  chloride  in  the  double  chloride 

*  The  filter  tube  shown  in  photo  No.  15  contains  a  rubber  gasket  and  alundum 
thimble;  these  are  removed  and  a  perforated  porcelain  plate  is  substituted  for 
the  carbon  filtration. 


CARBON  IN  PLAIN   STEEL  AND   ALLOY   STEELS  249 

solution  causes  the  metallic  copper  formed  to  pass  into  solution 
in  the  manner  shown  in  reaction  (2),  CuCl2  +  Cu  =  2CuCl. 
This  cuprous  chloride  (CuCl)  would  form  and  separate  out  as 
a  white  precipitate  were  it  not  for  the  excess  of  acid  present  in 
the  double  chloride  which  excess  of  HC1  dissolves  the  cuprous 
chloride;  hence  it  is  best  to  wash  the  carbon  residue  on  the 
asbestos  filter  at  first  with  some  of  the  double  chloride  before 
washing  it  with  water. 

The  carbon  is  filtered  on  an  asbestos  filter  supported  on  a 
perforated  porcelain  plate  just  large  enough  to  fit  in  a  glass 
carbon  filter  tube  of  i|  inches  diameter.  This  filter  is  pre- 
pared in  exactly  the  same  way  as  described  for  the  larger  filter 
used  for  the  double  chloride.  A  row  of  four  of  these  carbon 
filter  tubes  are  shown  in  photo  No.  15.  The  well  tamped 
and  acid  shrunken .  layer  of  asbestos  need  not  be  over  J  inch 
thick.  The  dissolved  chips  are  poured  through  the  asbestos 
filter  and  any  black  particles  of  carbon  adhering  to  the  walls 
of  the  beaker  are  best  discovered  by  holding  the  latter  over  a 
sheet  of  white  paper.  These  particles  are  transferred  to  the 
filter  by  rubbing  them  loose  with  a  rubber  capped  glass  rod, 
rinsing  the  beaker  with  a  fine  jet  of  water  and  also  some  of  the 
double  chloride.  The  carbon  being  now  all  on  the  asbestos  it  is 
washed  five  times  with  some  of  the  double  chloride,  drawing 
off  each  washing  with  mild  suction.  The  acid  is  then  carefully 
removed  by  giving  the  filter  thirty  washings,  drawing  off  each 
one  entirely  before  the  next  washing  is  applied.  The  carbon 
filter  tube  is  then  withdrawn  from  the  rubber  stopper.  The 
porcelain  plate  with  its  adhering  asbestos  and  carbon  is  carefully 
pushed  out  of  the  filter  tube  on  to  a  clean  watch  glass,  with  the 
plate  side  down.  Any  carbon  sticking  to  the  walls  of  the  filter 
tube  is  completely  removed  by  wiping  them  off  with  some  of 
the  asbestos.  The  top  part  of  the  asbestos  filter  is  first 
stripped  off  and  placed  in  the  clay  combustion  boat.  This 
leaves  all  of  the  rest  of  the  filter  to  be  used  in  cleaning  out  the 
filter  tube.  This  portion  of  the  filter  is  now  moistened  with 
water.  A  pair  of  steel  forceps  that  are  not  too  stiff  are  used  to 


250  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

hold  the  portions  of  the  dampened  filter  that  are  used  for  re- 
moving carbon  that  sticks  to  the  filter  tube.  Then,  at  the  last, 
the  points  of  the  forceps  should  be  wiped  off  with  a  little  of  the 
pulp  as  some  of  the  carbon  is  likely  to  be  on  the  forceps. 
The  operator  should  wash  his  hands  before  beginning  the  trans- 
fer of  the  carbon  filter  and  the  cleanings  to  the  clay  boat. 
A  piece  of  stout  wire  or  a  glass  rod  is  used  for  pushing  the 
plate  and  the  adhering  filter  out  of  the  filter  tube.  Dry  the 
contents  of  the  boat  in  a  water  or  air  oven  for  two  or  three  hours. 
When  dry,  as  shown  by  there  being  no  noticeable  condensation 
upon  a  cold  watch  glass  placed  over  the  boat  immediately 
after  the  latter  has  been  taken  hot  from  the  air  bath,  the  contents 
of  the  boat  are  pressed  firmly  down  into  it  and  four  grams  of 
red  lead  are  spread  over  the  same.  The  boat  is  then  placed 
in  the  electric  furnace  and  the  carbon  is  finished  in  the  same 
manner  as  given  for  the  direct  combustion.  Prior  to  the  burn- 
ing, the  water  should  not  be  dried  out  of  the  residue  in  the  boat 
at  a  temperature  exceeding  100°  C.  The  blank  is  run  by  plac- 
ing the  same  amount  of  the  double  chloride  in  a  beaker;  filter- 
ing it  through  a  filter  made  as  in  an  actual  sample  and  putting 
this  filter  through  all  of  the  operations  just  described,  including 
the  red  lead  covering. 


CHAPTER  XI. 

PART  V. 
GRAPHITE  IN  IRON  AND   GRAPHITIC   CARBON  IN  STEEL. 

IN  steels  dissolve  3  or  4  grams  of  drillings  in  60  c.c.  of  1.20 
nitric  acid,  boil  slowly,  avoiding  the  concentration  of  the  nitric 
acid  by  adding  a  little  water  if  necessary,  until  the  flakes  of 
combined  carbon  are  dissolved.  Perfectly  annealed  steel  in 
which  graphitic  carbon  is  most  frequently  found,  does  not  show 
this  flake  and  the  heating  is  continued  until  the  main  solution 
no  longer  continues  to  grow  any  clearer.  This  requires  about 
ten  minutes  boiling. 

In  pig  iron  i  gram  is  dissolved  in  20  c.c.  of  the  above  acid 
aided  with  2  or  3  drops  of  HF1,  boiling  10  minutes.  The  insol- 
uble matter  is  filtered  on  the  same  kind  of  an  asbestos  filter  as 
is  described  for  carbon  in  steel  where  the  chips  are  dissolved  in 
the  double  chloride  of  potassium  and  copper. 

The  residue  on  the  filter  is  washed  thirty  or  forty  times  with 
water  to  remove  the  iron;  then  with  i.i  specific  gravity  KOH 
solution  which  is  made  by  dissolving  30  grams  of  KOH  in 
200  c.c.  of  water.  The  washing  with  the  KOH  is  continued 
until  the  washings  are  no  longer  colored  brown.  Then  wash 
with  water  as  many  times  as  before;  then  with  i  :  i  HC1  to 
neutralize  any  remaining  KOH;  and  finally  again,  thoroughly, 
with  water.  The  graphitic  residue  is  removed  from  the  filter, 
dried,  covered  with  red  lead,  and  finished  as  described  in  the 
direct  method  for  carbon  in  steel,  in  the  electric  furnace. 

The  filtrate  from  the  carbon  or  graphite,  in  this  method, 
or  in  the  double  chloride  method,  should  be  poured  through  a 
filter  paper  and  washed  free  of  color  to  note  if  any  black  stain 
remains  on  the  filter;  if  there  be  such  a  stain  then  some  of  the 
carbon  or  graphite,  as  the  case  may  be,  has  run  through  and  the 
result  will  be  too  low. 

251 


CHAPTER  XII. 

PART  I. 
CARBON  BY  COLOR. 

THE  determination  of  carbon  by  color  methods  should  be 
indulged  in  as  little  as  possible.  Numerous  interferences  render 
analysis,  unless  carried  out  under  the  guidance  of  persons  of 
long  experience,  highly  inaccurate.  The  heat  treatment,  i.e., 
the  greater  or  less  amount  of  incidental  annealing  that  a  sample 
may  have  had,  will  cause  the  color  to  vary,  yielding  results  from 
10  per  cent  to  20  per  cent  away  from  the  actual  carbon.  The 
perfectly  annealed  steel,  i.e.,  where  the  carbon  has  all  been 
converted  into  the  absolutely  annealed  condition,  yields  the 
greatest  depth  of  color  for  a  given  percentage.  A  few  tenths  of 
a  per  cent  of  highly  coloring  elements  like  chromium  give  low 
results  compared  with  a  standard  steel  not  containing  the  alloy. 
Also  the  presence  of  considerable  manganese  tends  to  lighten 
the  color  in  unannealed  steel.  The  same  is  true  of  nickel. 

If  a  sample  consisting  of  large,  bulky,  thick  drillings  be  com- 
pared with  a  standard  of  small,  uniform  size,  thin  drillings,  the 
bulky  sample  will  yield  results  often  10  per  cent  too  low.  The 
presence  of  graphitic  carbon  will  cause  results  to  be  anywhere 
from  5  per  cent  to  90  per  cent  too  low.  Of  course,  much  graphitic 
carbon  is  easily  detected  by  the  insoluble  black  residue  that 
remains  in  the  solution  so  that  only  5  per  cent  too  low  is  likely 
to  be  unnoticed.  A  practiced  eye  will  detect  the  slightest 
trace  of  it.  If  the  operator  can  drill  his  own  samples  and  always 
get  them  with  the  same  heat  treatment,  and  have  a  standard 
that  has  undergone  the  same  treatment,  and  has  been  drilled 
with  the  same  depth  of  cut,  his  results  will  be  fairly  accurate. 

There  are  two  means  by  which  one  may  approach  the  ideal: 

252 


CARBON   BY  COLOR  253 

First.  When  the  drillings  to  be  tested  and  the  standard  drill- 
ings have  been  taken  from  the  raw  cast  steel  that  has  never 
been  reheated  and  is  always  allowed  to  cool  slowly  from  the 
molten  state,  i.e.,  without  any  quenching.* 

Second.  Where  the  operator  is  furnished  the  steel  and  can 
anneal  it  to  the  last  degree  of  softness,  avoiding  the  temperature 
range  most  favorable  to  the  formation  of  graphitic  carbon  (see 
Annealing  of  Steel).  Then  drill  such  samples  to  uniform  thick- 
ness and  compare  them  with  a  standard  prepared  in  exactly 
the  same  manner.  This  second  scheme  is  the  most  accurate 
of  all  color  methods.  For  the  identification  of  the  perfectly 
annealed  condition,  see  Annealing. 

Further,  it  is  essential  in  color  work  that  the  standard  shall 
be  within  10  per  cent  of  the  carbon  content  of  the  sample  to  be 
tested.  The  nearer  the  carbon  of  the  standard  is  to  that  of  the 
test,  the  better;  especially  is  this  true  of  unannealed  steel. 

Method.  Dissolve  100  mgs.  of  sample  in  4  c.c.  of  1.20  nitric 
acid.  Use  a  test  tube  152  mm.  by  15  to  16  mm.  diameter. 
Insist  that  the  dealer  supply  test  tubes  that  keep  within  the 
same  diameter.  If  one  test  tube  is  wide  and  its  mate  narrow, 
the  wide  one  will  permit  more  of  the  free  acid  to  escape  than 
the  narrow  one,  causing  variation  in  the  color.  Do  not  set  the 
tubes  deep  in  the  boiling  water,  as  it  will  cause  iron  to  dry  on 
the  sides,  and,  when  this  is  redissolved  by  shaking  the  hot  acid 
solution  the  brown  basic  nitrate  of  iron  will  go  into  solution, 
causing  another  variation  of  color.f  The  fewer  tests  dissolved 
at  one  time  the  better,  as  some  parts  of  the  bath  will  be  hotter 
than  others,  causing  more  loss  of  acid  from  the  tubes  in  the 
hotter  location.  In  forty  minutes  all  of  the  flakes  of  carbon 
are  usually  dissolved  on  a  water  bath.  These  baths  are  de- 
signed especially  for  this  work,  and  contain  racks  to  hold  thirty- 
six  tubes.  These  racks  have  false  bottoms  perforated  with 
many  small  holes.  This  arrangement  permits  the  tubes  to  be 

*  Quenching  can  be  safely  done  provided  the  test  piece  is  first  cooled  to  a  black 
heat  in  an  entirely  dark  closet. 

t  Some  laboratories  use  glass  marbles  that  rest  on  the  top  of  the  test  tubes 
during  the  boiling  to  reduce  the  evaporation  of  the  acid. 


254  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

immersed  to  the  depth  of  28  mm.,  which  is  about  the  level  of 
the  nitric  acid. 

For  more  rapid  solution  of  the  carbon,  requiring  from  four  to 
seven  minutes,  use  a  sand  or  graphite  bath  heated  to  about  190° 
C.  Plunge  the  tubes  into  the  bath  just  to  the  top  level  of  the 
acid  in  them.  Keep  the  tubes  close  together  and  do  not  run  more 
than  six  tubes  at  a  time,  as  such  a  bath  is  liable  to  great  varia- 
tion in  temperature.  The  writer  collects  a  set  of  six  tubes  in  a 
compact  cluster  and  covers  all  with  a  5-ounce  beaker.  This 
prevents  too  rapid  loss  of  acid.  Remove  the  tests  the  second 
that  the  brown  flakes  are  in  solution.  Use  standards  within  5 
"points"  (0.05  per  cent  carbon)  of  the  tests  so  that  tests  and 
standards  will  go  into  solution  at  about  the  same  moment. 

The  tests  are  quickly  cooled  in  running  water  and  compared 
in  the  bent-end  comparison  tubes,  which  permit  the  contents 
of  the  tubes  to  be  mixed  by  a  rocking  motion.  The  comparison 
tubes  are  of  14  c.c.  capacity,  and  graduated  to  tenths  of  a  c.c. 
The  length  of  the  graduated  portion  is  181  mm.  Then  follows 
45  mm.  of  ungraduated  tube;  then  the  part  bent  at  an  obtuse 
angle.  The  bent  limb  is  about  50  mm.  long.  The  outside 
diameter  of  the  tube  is  12  mm.  A  set  of  three  of  these  tubes  is 
used.  The  specifications  for  these  tubes  should  require  that  all 
three  tubes  be  the  same  inside  and  outside  diameter  throughout 
their  graduated  portion.  The  figures  and  graduation  lines 
should  be  small,  the  figures  not  over  2  mm.  long  and  the  lines 
not  over  4  mm.  long  for  c.c.,  and  not  over  i|  mm.  long  for  tenths 
of  a  cubic  centimeter. 

The  graduations  of  all  three  tubes  should  coincide  with  each 
other.  For  example,  the  14  c.c.  mark  should  be  exactly  the 
same  distance  from  the  bottom  of  the  comparison  tube  in  each 
tube  of  a  set,  thus  proving  that  the  inside  diameter  is  uniform 
throughout  the  set. 

The  tubes  should  be  free  of  fine  black  lines  due  to  bubbles  in 
the  glass  when  it  was  drawn  into  tubing. 

The  tubes  should  be  made  of  selected  tubing  free  of  scratches. 
The  graduations  should  be  as  exact  as  those  of  a  burette. 


CARBON   BY   COLOR  255 

All  color  carbons  should  be  made  in  duplicate  and  results 
averaged.  Nothing  is  gained  by  operating  on  a  greater  amount 
than  o.ioo  gram.  The  writer,  in  his  practice,  ran  a  great  many 
color  tests,  using  0.500  gram,  and  found  the  same  lack  of  agree- 
ment, and  much  more  acid  is  needed. 

The  Comparison.  If,  for  example,  a  0.60  carbon  standard  is 
in  use  pour  it  into  the  comparison  tube,  using  as  little  rinse  water 
as  possible,  so  that  the  volume  of  the  fluid  in  the  tube  is  just 
6  c.c.;  mix  thoroughly. 

The  test  is  then  put  in  another  tube,  and  water  is  added  to 
it  until  its  color  is  the  same  shade  as  that  of  the  standard,  mixing 
carefully  with  each  addition  of  water.  This  matching  should  be 
conducted  slowly  when  the  test  is  still  but  slightly  darker  than 
the  standard.  But  two-tenths  of  a  cubic  centimeter  should  be 
added  at  a  time  when  the  test  is  only  slightly  darker  than  the 
standard,  so  that  when  the  former  is  finally  very  slightly  lighter 
than  the  standard,  the  operator  knows  he  has  overstepped  the 
end  point  o.oi  per  cent,  which  he  deducts  from  the  reading.  If 
the  test,  for  example,  is  just  turned  lighter  at  6.5  c.c.,  then  the 
per  cent  carbon  will  be  0.65  less  o.oi  or  0.64  per  cent  carbon.  If 
a  standard  of  0.30  carbon  is  in  use,  it  is  diluted  to  9.0  c.c.  Should 
the  test  match  it  at  6.0  c.c.,  then  the  carbon  percentage  will  be 
0.60  -f-  3,  or  0.20  per  cent  carbon.  If  a  standard  of  0.40  carbon 
is  used,  it  is  diluted  to  8.0  c.c.  If  the  test  matches  it  at  7.0  c.c. 
for  example,  then  the  per  cent  carbon  will  be  0.70  -f-  2,  or  0.35 
per  cent  carbon.  If  a  standard  of  0.08  per  cent  carbon  is  in  use, 
it  is  diluted  to  5.6  c.c.  Should  the  test  match  it  at  6.0  c.c.,  for 
example,  the  per  cent  carbon  would  be  0.60  -r-  7,  or  0.085  — 
per  cent  carbon.  When  a  large  number  of  color  tests  must  be 
made,  they  should  be  checked  at  frequent  intervals  by  combustion; 
for  instance,  if  a  lot  of  30  color  tests  are  made,  and  every  fifth 
one  is  checked  by  combustion  and  checks  within  o.oi  to  0.03 
per  cent  in  a  range  from  0.50  per  cent  and  over,  it  is  pretty  safe 
to  assume  that  that  particular  lot  of  color  tests  was  done  under 
favorable  conditions. 

The  writer  does  not  use  a  comparison  camera,  but  decidedly 


256  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

prefers  to  hold  the  tubes  on  a  sheet  of  white  paper  in  diffused 
sunlight.  The  direct  glare  of  the  sun  is,  of  course,  undesirable. 

At  night  a  5o-candle  power  frosted  electric  lamp  of  filament 
type  resting  on  a  sheet  of  white  paper  from  a  flexible  arm  is 
the  best  source  of  light.  The  comparison  tubes  should  be  held* 
with  the  graduations  touching  each  other,  thus  giving  a  clear 
field  of  color.  Their  relative  right  and  left  positions  should 
be  changed  at  intervals  of  a  few  seconds  to  assist  the  operator 
in  judging  respective  depths  of  color.  He  should  endeavor  to 
lose  track  of  which  is  test  and  which  is  standard,  and  if,  under 
such  conditions,  he  finds  he  can  come  to  the  same  conclusion 
three  times  in  succession,  then  he  is  as  certain  as  possible  of  his 
choice  of  the  light  one  and  the  dark  one.  In  the  writer's  opinion 
the  least  source  of  error  in  carbon  color  work  is  the  operator's 
eye.  A  man  with  a  good  eye  for  color  and  plenty  of  practice 
can  be  counted  on  not  to  introduce  an  error  due  to  the  eye  of 
over  0.02  per  cent  in  higher  carbons  and  of  not  over  o.oio  per 
cent  in  lower  carbons,  around  o.o&  and  perhaps  not  over  0.005 
per  cent  in  the  latter  range. 

Reject  all  drillings  that  are  blued,  or  rusty. 

*  The  comparison  tubes  should  be  held  at  an  angle  of  about  45  degrees  to  the 
paper  with  their  ends  touching  the  same. 


CHAPTER  XII. 

PART  II. 

VOLUMETRIC  PHOSPHORUS  IN  PIG  IRON,  STEEL,  WASHED 
METAL  AND  MUCK  BAR.* 

DISSOLVE  1.63  grams  of  sample  in  45  c.c.  1.13  nitric  acid, 
using  a  5  ounce  beaker.  Heat  gently  on  hot  plate  or  bath 
of  some  description.  The  writer  uses  a  twelve-hole  affair  as 
shown  in  Fig.  16.  Highly  silicious  pig  iron  dissolves  slowly 
and  it  is  best  to  maintain  all  pig  iron  samples  at  digesting  heat 
(barely  boiling)  for  at  least  twenty  minutes.  To  assist  in 
dissolving  pig  iron  add  four  drops  of  hydrofluoric  acid  to  the 
solution  after  it  has  been  digested  ten  minutes  with  the  nitric 
acid,  if  high  silicon  is  suspected. 

For  pig  iron  and  some  chrome  steels  the  next  step  is  to  filter 
out  the  insoluble  graphite,  etc.  Wash  the  residue  on  the  filter 
fifteen  times  with  the  dilute  nitric  acid  wash.  All  phosphorus 
nitrations  in  this  laboratory  are  made  on  a  revolving  filter 
stand.  (See  Fig.  17.) 

It  is  not  necessary  to  filter  solutions  in  plain  carbon  steels. 
Filter  the  muck  bar  solutions  if  they  contain  much  insoluble 
residue. 

Add  to  the  filtered  solutions  of  pig  iron,  chrome  steel  and 
muck  iron  and  to  the  unfiltered  solutions  of  plain  steel  and 
washed  metal,  from  a  convenient  drop  bottle,  the  potassium 
permanganate  solution.  Continue  the  addition  of  perman- 
ganate until  the  excess  of  manganese  separates  as  a  brown 
precipitate  that  does  not  disappear  noticeably  after  10  minutes 
boiling.  As  washed  metal  usually  contains  about  3.00  per  cent 
of  carbon  it  will  consume  considerably  more  of  the  perman- 

*  Hundeshagen  (modified  by  J.  O.  Handy)  first  recommended  the  titration 
of  the  yellow  precipitate  by  standard  alkali. 

257 


258 


CHEMICAL  ANALYSIS  OF  "SPECIAL  STEELS 


ganate  solution  before  the  carbon  is  destroyed  than  ordinary 
steel.  The  excess  of  manganese  precipitate  is  removed  by 
adding  ferrous  sulphate  solution,  free  of  phosphorus,  from  a 
dropper  until  the  solution  is  again  clear.  After  five  minutes 
more  boiling  the  beakers  are  removed  from  the  fire,  the  covers 
are  rinsed  off  and  the  inside  walls  of  the  beakers  are  washed 


FIG.  1 6. 

Phosphorus  in  steel. 

(to  prevent  the  phospho-rnolybdate  sticking  to  the  walls)  down, 
and  50  c.c.  of  the  ammonium-molybdate*  are  run  into  each  test 
from  a  measuring  siphon.  (See  Fig.  18.)  A  batch  of  12  tests 
are  stirred  at  a  time,  using  glass  rods.  A  single  test  is  stirred 
around  twice,  then  the  next  one,  and  so  on  until  each  test  in 
the  lot  has  been  stirred  ten  times.  This  means  that  each  solu- 
tion has  been  stirred  at  intervals  during  a  period  of  ten  minutes. 
The  twelve  samples  are  put  on  the  revolving  stand  and  twelve 
7  cm.  niters  are  marked  with  a  lead  pencil  to  correspond  to  the 
respective  tests.  The  only  interval  between  the  completion 
of  the  stirring  and  commencement  of  the  filtration  is  the  time 
required  to  fit  the  filter  papers  to  the  funnels. 

The  liquid  is  decanted  through  its  proper  filter  and  the  bulk 
of  the  precipitate  is  allowed  to  remain  in  the  beaker  until  the 


*  H3P04  +  12  (NH4)2Mo04  +  21  HNO3 
12  H20. 


(NH4)3P04-i2  Mo03  +  21 


VOLUMETRIC   PHOSPHORUS  IN  PIG  IRON,  STEEL,  ETC.      259 

filter  papers  are  washed  ten  times,  giving  each  paper  a  washing, 
then  the  next  one  and  so  on  until  number  one  is  reached  again. 
By  the  time  number  one  is  ready  for  its  second  washing,  the 
first  washing  will  be  well  drained  off.  Each  funnel  stem  is 
given  a  turn  with  the  thumb  and  forefinger  in  such  a  manner 


FIG.  17. 

Phosphorus  in  steel. 


FIG.  1 8". 

Phosphorus  in  steel. 


that  the  double  fold  of  the  paper  is  washed  twice  and  the  single 
fold  once  during  each  washing.  Use  the  dilute  nitric  acid  wash. 
Ten  washings  having  been  accomplished,  the  main  body 
of  the  yellow  precipitate  is  washed  on  to  its  respective  filter 
with  a  fine  jet  of  the  acid  wash,  and  receives  a  further  ten  wash- 
ings to  remove  iron. 


260  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

To  remove  free  acid  the  precipitates  are  next  washed  thirty 
times  with  the  potassium  nitrate  water.  The  niters  are  now 
removed  to  a  large  watch  glass.  A  ruled  slip  is  dated  and  headed 
and  the  various  tests  are  entered  thereon.  On  the  right-hand 
side  is  kept  a  record  of  the  alkali  used,  and  on  the  left,  the  acid 
standard  used  in  the  subsequent  titration  of  the  yellow  pre- 
cipitate. 

The  titration  is  accomplished  by  placing  filter  and  precipitate 
In  a  100  c.c.  beaker.  The  standard  sodium  hydroxide  solution, 
i  c.c.  of  which  equals  o.oi  per  cent  phosphorus  when  1.63  grams 
are  taken,  is  dropped  on  the  filter  until  the  yellow  precipitate 
has*  dissolved.!  Then  add  50  c.c.  distilled  water.  Two  drops 
of  phenolphthaleine  are  introduced,  and  from  a  second  50  c.c. 
burette  standard  nitric  acid  is  run  into  the  rose  colored  solution 
until  one  drop  of  acid  discharges  this  color.  The  total  number 
of  c.c.  of  alkali  added,  less  the  number  of  c.c.  of  acid  required  to 
discharge  the  rose  color,  multiplied  by  o.oi,  gives  the  percentage 
of  phosphorus  in  the  sample.t 


GRAVIMETRIC  PHOSPHORUS. 

If  it  is  desired  to  check  the  volumetric  method  by  weigh- 
ing the  yellow  precipitate,  proceed  exactly  as  given  under  the 
latter  process,  with  the  following  exceptions: 

First.     Filter  all  solutions  as  in  pig  iron. 

Second.  Omit  the  washing  with  potassium  nitrate  and  use 
only  the  dilute  nitric  wash  to  remove  iron,  leaving  the  acid  in 
the  filter  paper. 

Third.  Filter  the  yellow  precipitate  on  7  cm.  ashless  filters 
that  have  been  previously  weighed  hot  between  watch  glasses 
with  edges  ground  to  fit  water-tight  when  held  firmly  together, 
nearly  full  of  water,  in  a  vertical  position. 


*  The  following  equation  explains  how  the  solution  takes  place: 
i2MoO3  +  24NaOH  =  (NH4)3PO4  +  i2Na2MoO4  +  i2H2O. 

t  It  is  safer  to  add,  at  least,  i  or  2  c.c.  excess  of  the  alkali  standard. 

t  Figs.  16,  17  and  18  were  designed  some  years  ago  by  Dr.  Edward  S.  Johnson. 


VOLUMETRIC  PHOSPHORUS   IN  PIG  IRON,   STEEL,  ETC.      261 

These  filters  are  weighed  as  rapidly  as  possible  after  having 
been  dried  at  the  temperature  of  boiling  water.  The  phospho- 
molybdate  is  collected  on  the  weighed  filters  and  washed  free 
from  iron  with  the  dilute  nitric  acid.  The  filters  are  again  dried 
as  before,  for  one  hour,  and  weighed.  The  weight  of  the  filter 
paper  plus  the  dried  precipitate,  less  the  weight  of  the  paper, 
less  the  blank  (obtained  by  filtering  a  clear  filtrate  from  some 
previous  phosphorus  determination  through  a  weighed  paper, 
washing  it,  drying  it  and  reweighing  it  as  in  an  actual  analysis) 
equals  the  percentage  in  the  sample  when  1.63  grams  are  used 
for  analysis.  This  method  is  valuable  only  as  a  check,  as  too 
much  time  is  consumed. 

In  both  methods  the  filtrates  and  washings  are  placed  on  a 
shelf  for  one  hour.  If  a  cloudy  ring  forms  at  the  junction  of  the 
washings  and  the  main  body  of  the  filtrate,  results  will  be  too 
low.  If  the  cloud  gradually  spreads,  the  results  may  be  as  much 
too  low  as  o.oi  per  cent  in  a  possible  o.ioo  per  cent. 

After  considerable  practice  one  can  estimate  with  sufficient 
accuracy  for  most  mill  control  all  phosphorus  0.02  per  cent 
and  under  by  simply  examining  the  yellow  precipitate  after 
it  has  had  an  opportunity  to  settle  for  about  twenty  minutes 
in  the  5-ounce  beaker.  The  prevention  of  cloudy  filtrates  will 
be  discussed  under  the  heading  "Molybdate  Solution." 

STANDARD  SODIUM  HYDROXIDE  SOLUTION. 

One  hundred  and  fifty  grams  of  sodium  hydroxide  and  one 
gram  of  barium  hydroxide  are  dissolved  in  1000  c.c.  of  water. 
Let  the  solution  stand  for  two  days.  Siphon  off  the  fluid  and 
dilute  it  to  two  liters.  Dilute  275  c.c.  of  this  stock  solution 
to  3500  c.c.  On  testing,  suppose  it  is  found  that  20  c.c.  of  the 
alkali  standard  equal  20.75  c-c-  °f  tne  acid  standard.  This 
gives  the  proportion  20  :  20.75  : :  34°o  '%(  =  3527).  There- 
fore dilute  the  remaining  3400  c.c.  to  3527  c.c.  when  20  c.c.  of 
the  NaOH  standard  will  equal  20  c.c.  of  the  standard  acid  or 
i  c.c.  NaOH  =  o.oio  per  cent  phosphorus  when  1.63  grams  of 


262  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

sample  are  used  for  analysis.  It  is  always  best  to  confirm  this 
value  by  running  several  steels  whose  phosphorus  content  is 
accurately  known. 

STANDARD  NITRIC  ACID. 

Dilute  74  c.c.  1.20  nitric  acid  to  3500  c.c.  On  titrating  with 
standard  NaOH,  suppose  it  is  found  that  19.2  c.c.  of  the  acid 
equal  20  c.c.  of  the  alkali  :  19.2  c.c.  :  20  c.c.  :  :  3400  :  x  (  —  3541). 

Therefore  the  remaining  3400  c.c.  are  diluted  to  3541  c.c.  when 
20  c.c.  of  standard  acid  should  equal  20  c.c.  of  standard  alkali. 

For  preparation  of  1.20  specific  gravity  nitric  acid  from 
concentrated  acid  see  Chapter  XX. 

MOLYBDATE   SOLUTION. 

Dissolve  183  grams  of  unignited  molybdic  acid  plus  2  grams 
of  ignited  (melted)  molybdic  acid  in  900  c.c.  of  11.50  per  cent 
ammonia  water  plus  250  c.c.  of  distilled  water.  Cool  this 
solution  and  add  it  a  little  at  a  time  to  2700  c.c.  1.20  nitric 
acid.  Cool  the  nitric  acid  after  each  addition  of  the  molybdate. 
If  the  nitric  acid  is  allowed  to  get  too  greatly  heated  the  molybdic 
salt  will  precipitate  in  large  quantity.  Filter  through  a  pulp 
filter  (using  suction)  after  twelve  hours'  standing. 

Some  years  ago  the  writer  observed  that  a  solution  of  am- 
monium molybdate  in  nitric  acid,  made  as  here  given,  will 
produce  different  varieties  of  the  yellow  precipitate.  Other  con- 
ditions being  unchanged,  an  ammonia  solution  of  molybdic  acid 
prepared  from  ignited,  i.e.,  crystalline  anhydrous  molybdic 
acid,  causes  the  yellow  precipitate  to  separate  from  the  nitric 
acid  solution  of  the  steel  in  an  extremely  fine  state  of  division. 
Such  a  precipitate  will  remain  suspended  in  the  solution  for 
hours  without  subsiding  and  will  run  through  a  filter  paper 
almost  as  though  it  were  a  solution  instead  of  a  precipitate. 
This  precipitate  has  only  one  redeeming  feature:  It  is  the  least 
soluble  in  the  dilute  nitric  wash  of  any  of  the  varieties  of  ammo- 
nium phospho-molybdate  that  are  encountered  under  the  con- 
ditions that  are  cited  here.  Now  if  no  ignited  molybdic  acid 


VOLUMETRIC   PHOSPHORUS   IN  PIG  IRON,   STEEL,  ETC.      263 

is  used  in  the  preparation  of  the  molybdate  solution,  the  phospho- 
molybdate  settles  rapidly  and  does  not  run  through  a  filter. 
But  this  variety  has  the  objection  that  it  is  the  most  soluble 
form  of  phospho-molybdate,  in  nitric  acid.  This  variety  of 
precipitate  will  leave  the  filtrate  perfectly  clear,  but  after  the 
latter  has  stood  for  an  hour  (if  much  precipitate  has  dissolved 
in  the  wash  water)  or  perhaps  not  until  the  next  day  (if  little  of 
the  yellow  precipitate  has  dissolved  in  the  dilute  nitric  wash)  a 
milky  ring  of  phospho-molybdate  will  appear  at  about  the  point 
where  the  washings  lie  on  top  of  the  main  body  of  the  filtrate. 
If  much  of  the  yellow  precipitate  has  been  dissolved,  say  about 
YO  or  ^V  °f  its  weight,  this  cloud  will  spread  through  the  entire 
filtrate. 

The  ideal  yellow  precipitate  is  that  one  whose  physical  condition 
is  such  that  it  will  give  a  clear  filtrate  and  be  practically  insoluble 
in  the  wash.  The  author  has  had  brands  of  molybdic  acid  that 
require  equal  weights  of  the  crystalline  molybdic  acid  and  of 
the  unignited  variety  to  produce  the  desired  results.  At  present 
but  2  grams  of  the  crystalline  material  are  needed  for  the  partic- 
ular brand  of  molybdic  acid  now  in  use. 

To  prepare  crystalline  molybdic  acid  the  author  melts  in 
a  porcelain  dish  the  ammonia-free,  so-called  c.p.,  molybdic 
acid  which  melts  rapidly  at  a  bright  red  heat  to  a  clear  fluid, 
and,  on  cooling,  forms  handsome  crystals  that  can  be  readily 
reduced  to  a  powder  in  a  porcelain  mortar. 


POTASSIUM  PERMANGANATE  SOLUTION  FOR  OXIDATION 
OF  THE  CARBON. 

Fifty  grams  of  the  salt  dissolved  in  one  liter  of  water. 


FERROUS  SULPHATE  SOLUTION. 

Two  hundred  and  fifty  grams  of  the  phosphorus-free  salt 
dissolved  in  1000  c.c.  of  water  acidulated  with  20  c.c.  i  :  3 
sulphuric  acid. 


264  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

DILUTE  NITRIC  ACID  WASH. 

Two  hundred  and  thirty  c.c.  1.20  nitric  acid  diluted  with 
8100  c.c.  of  water. 

POTASSIUM  NITRATE  WASH. 

Dissolve  50  grams  of  potassium  nitrate  in  2500  c.c.  of  water 
for  a  stock  solution. 

Dilute  700  c.c.  of  the  latter  with  7000  c.c.  of  water  to  con- 
stit'ute  the  wash. 

PHENOLPHTHALEINE  INDICATOR. 

One  gram  of  this  substance  is  dissolved  in  100  c.c.  of  absolute 
alcohol.* 

PHOSPHORUS  IN  VANADIUM  STEEL. 

E.  W.  Hagmaier,  in  Met.  Chem.  Eng.,  Vol.  XI,  No.  i,  separates 
the  phosphorus  by  cerium  chloride.  In  the  case  of  a  tungsten 
steel,  dissolve  the  steel  as  for  tungsten  as  given  on  pages  98  to 
ico.  Instead  of  adding  the  molybdate  solution  as  directed  on 
page  ico,  this  chloride  solution  should  be  entirely  reduced  with 
SO2;  then  add  5  c.c.  of  90  per  cent  acetic  acid  and  10  c.c.  of  a 
saturated  solution  of  cerium  chloride.  Next  add  i  :  3  ammonia 
slowly  until  a  permanent  turbidity  is  obtained.  Boil;  let  settle; 
filter;  wash  a  few  times  with  hot  water;  dissolve  in  i  :  i  hot 
nitric  acid  and  precipitate  the  phosphorus  with  molybdate  solu- 
tion. If  the  vanadium  is  in  excess  of  i  per  cent,  the  cerium 
phosphate  must  be  redissolved,  and  reprecipitated  to  remove  all 
of  the  vanadium.  The  cerium  phosphate  is  then  dissolved  off 
the  filter  with  the  nitric  acid  and  finished  as  above. 

*  See  remarks  at  the  close  of  Chapter  XI,  page  218,  on  the'proper  way  to  drill 
a  steel  sample  in  order  to  obtain  borings  that  represent  the  average  of  the  piece 
in  phosphorus,  sulphur,  silicon  and  carbon. 


CHAPTER  XII. 

PART  III. 
THE  ANALYSIS  OF  FERRO-PHOSPHORUS. 

SILICON. 

FUSE  0.5  or  0.6  gram  of  the  floured  sample  in  a  finely  ground 
mixture  of  10  grams  of  sodium  carbonate  and  2  grams  of  potas- 
sium nitrate  in  a  platinum  crucible.  After  a  complete  fusion 
is  gotten  as  shown  by  the  melt  being  practically  free  of  boiling 
at  a  bright  red  heat,  cool  the  melt  by  running  it  around  the 
sides  of  the  crucible;  dissolve  it  out  of  the  crucible  with  water 
in  a  platinum  dish;  transfer  the  water  solution  and  all  to  a  600 
c.c.  casserole,  cleaning  the  crucible  by  heating  in  it  some  cone. 
HC1;  add  the  cleanings  to  the  casserole  whose  contents  have 
been  meanwhile  acidulated  with  75  c.c.  of  cone.  HC1.  Heat  the 
casserole  with  a  watch  glass  on  it  until  all  effervescence  has  ceased; 
remove  the  cover  and  evaporate  to  dryness;  cool;  add  20  c.c. 
of  cone.  HC1;  heat  for  some  minutes  to  dissolve  the  iron;  add 
150  c.c.  of  water  and  heat  again  to  dissolve  the  sodium  salts; 
filter  out  the  silicic  acid  and  wash  it  free  of  iron  test  with  i  :  20 
HC1.  Burn  off  the  paper  containing  the  silicious  matter  in  a 
weighed  platinum  crucible  and  finish  it  as  in  steels,  using  HF1 
and  a  few  drops  of  H2SO4.  (See  page  286.)  The  residue  remain- 
ing after  volatilizing  the  silicon  may  contain  a  little  iron  and 
phosphorus.  Fuse  this  residue  with  20  times  its  weight  of 
anhydrous  sodium  carbonate;  dissolve  the  fusion  with  HC1 
and  add  the  solution  to  the  main  filtrate  from  the  silicious 
matter. 

PHOSPHORUS. 

The  main  filtrate  from  the  silicon  now  contains  all  of  the 
phosphorus  and  iron.  Dilute  this  filtrate  to  400  c.c.  with  water; 
add  2  grams  of  citric  acid,  to  keep  the  iron  from  reprecipitating, 

265 


266  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

and  then  a  slight  excess  of  ammonia.  Heat  the  solution  to 
nearly  boiling  and  pass  through  it  a  stream  of  hydrogen  sulphide 
that  has  been  washed  by  bubbling  through  a  wash  bottle  con- 
taining about  an  inch  of  distilled  water.  The  original  form  of  the 
2  quart  Kipp  is  the  most  practical  form  of  H^S  generator.  The 
iron  sulphide  that  is  supplied  fused  and  in  sticks  is  the  best  for 
this  work.  The  i  :  i  HC1  should  be  used  to  attack  the  iron 
sulphide.  When  the  black  sulphide  in  the  main  filtrate  has 
settled  out  well  and  falls  to  the  bottom  of  the  beaker,  stop  the 
stream  of  the  H3S  and  filter  out  the  sulphides  of  iron  and  some 
platinum  (the  crucible  is  attacked  some  by  the  niter  in  the  flux). 
Wash  the  sulphides  about  fifteen  times  with  water  saturated 
with  H^S.  Place  the  filter  containing  the  sulphides  in  a  por- 
celain dish  and  pour  over  it  30  c.c.  of  i  :  i  HC1  and  warm  it 
with  the  cover  on  at  riot  over  a  water  bath  temperature  for 
an  hour  to  dissolve  the  iron  sulphides.  If  platinum  is  present 
there  will  remain  some  insoluble  platinum  sulphide  which  can 
be  filtered  out  together  with  the  paper  pulp  from  the  first  filter 
which  was  placed  in  the  acid.  The  second  filter  is  washed  at  least 
twenty  times  with  i  :  40  HC1  and  then  further  until  the  washings 
no  longer  give  an  iron  test  with  either  potassium  ferricyanide 
or  with  ammonium  sulphocyanate.  This  filtrate  and  washings 
from  the  pulp  and  platinum  sulphide  contain  all  of  the  iron 
and  perhaps  still  a  portion  of  the  phosphorus.  2  grams  of  citric 
acid  are  again  added  and  the  iron  is  again  separated  in  hot  solu- 
tion with  H^S  as  before.  Filter  out  the  sulphide  of  iron  and  wash 
it  as  in  the  first  instance.  Retain  the  iron  sulphide  to  get  the 
total  iron.  The  two  sets  of  filtrates  and  washings  from  the 
H2S  precipitations  are  combined  and  made  acid  with  about  50  c.c. 
of  i  :  i  HC1  and  are  heated  with  a  cover  on  until  all  effervescence 
due  to  the  escape  of  H^S  is  over.  Remove  the  cover  and  evap- 
orate to  100  c.c. ;  add  water  if  necessary  to  dissolve  any  crystals 
that  may  have  formed;  filter  out  any  insoluble  matter;  add 
150  c.c.  of  cone,  nitric  acid  and  heat  in  the  covered  beaker  until 
all  action  between  the  nitric  acid,  the  chlorides,  and  the  citric 
acid  is  over;  then  transfer  to  a  large  casserole  and  evaporate 


THE  ANALYSIS  OF   FERRO-PHOSPHORUS  267 

low.  When  brown  fumes  begin  to  develop  again,  cover  the  ves- 
sel and  add  50  c.c.  more  of  the  cone.  HNOs.  Heat  until  all 
action  is  over;  remove  the  cover  and  evaporate  to  dryness; 
cool;  add  75  c.c.  of  cone.  HC1;  cover;  heat  until  action  ceases; 
evaporate  again  to  dryness;  cover  again;  add  once  more  75 
c.c.  of  HC1  and  evaporate  dry;  cool;  heat  with  25  c.c.  of  cone. 
HC1  with  the  cover  on  for  10  minutes;  add  150  c.c.  of  water  to 
dissolve  the  salts;  filter;  wash  the  filter  with  water  until  the 
washings  are  free  of  chlorides;  make  the  filtrate  and  washings 
just  neutral  with  ammonia;  cool;  add  40  c.c.  of  magnesia 
mixture;  stir  well;  add  to  the  solution  one- third  of  its  volume 
of  cone,  ammonia;  and  stir  the  solution  for  one  or  two  minutes 
and  let  it  stand  for  12  hours.  Then  filter  out  the  ammonium 
magnesium  phosphate  and  wash  it  with  5  c.c.  of  cone,  ammonia 
diluted  with  500  c.c.  of  water,  until  the  washings  no  longer  give 
a  cloudiness  after  being  acidulated  with  a  few  drops  of  dilute  nitric 
acid  and  tested  with  a  little  silver  nitrate  solution.  The  wash- 
ings should  be  kept  separate  from  the  main  filtrate.  Both  the 
filtrate  and  washings  should  be  tested  by  adding  10  c.c.  more  of 
the  magnesia  mixture  and  to  the  washings  should  be  also  added 
one-third  of  its  volume  of  ammonia.  If  any  precipitate  forms 
in  either  the  filtrate  or  the  washings  it  is  filtered,  washed  and 
added  to  the  main  precipitate.  Dry  the  filters  containing  the 
phosphate  precipitates,  and  then  smoke  off  the  volatile  portion 
of  the  filter  papers  below  redness  to  avoid  losing  particles  of  the 
phosphate;  do  not  heat  the  platinum  crucible  hot  enough  to 
ignite  the  gases  coming  from  the  papers.  When  the  smoking 
ceases,  raise  the  heat  to  low  redness,  and  finally  hot  enough  to 
obtain  a  pure  white  residue  of  magnesium  pyrophosphate.  Do 
not  use  a  blast  lamp  temperature  as  the  platinum  will  be  badly 
attacked  by  the  phosphate.  Weigh  the  Mg2P207;  dissolve  it 
in  HC1;  filter  out  any  insoluble  silica;  wash  it;  weigh  it  and 
deduct  it  from  the  first  weight;  calculate  the  net  weight  to 
metallic  phosphorus  by  use  of  the  factor  0.2787. 

Magnesia  Mixture  consists  of  25  grams  of  magnesium  chlor- 
ide, 50  grams  of  ammonium  chloride,  100  c.c.  of  cone,  ammonia 


268 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


and  200  c.c.  of  water.  This  mixture  is  stirred  until  the  salts 
are  dissolved,  and  after  standing  for  at  least  24  hours  it  is  fil- 
tered for  use. 

Sulphur  in  ferro-phosphorus  is  obtained  by  fusing  the  finely 
ground  sample  as  given  for  phosphorus,  continuing  the  analysis 
exactly  as  for  this  element  until  the  silicon  has  been  filtered  off. 
The  filtrate  and  washings  from  the  silicious  matter  are  then 
diluted  to  400  c.c.  and  the  sulphur  is  precipitated  with  BaCl> 
using  25  c.c.  of  a  saturated  solution  of  the  barium  salt.  The 
barium  sulphate  is  filtered  off  after  12  hours  and  the  deter- 
mination is  then  finished  as  in  steels. 

Iron  is  obtained  from  the  sulphide  gotten  from  the  second 
precipitation  with  H^S  in  the  analysis  for  phosphorus.  The  % 
sulphide  is  roasted  in  a  porcelain  crucible  until  free  of  the  paper ; 
the  ash  is  dissolved  in  HC1;  reduced  with  stannous  chloride 
and  titrated  with  potassium  dichromate  as  in  iron  ore.  The 
iron  can  also  be  obtained  in  the  sulphur  determination  by  fusing 
i  gram  of  the  sample  as  above  for  sulphur;  the  filtrate  from 
the  silicious  matter  can  be  divided  into  two  equal  parts  and  one 
part  can  be  finished  for  sulphur  and  the  other  half  is  precipi- 
tated with  ammonia  to  remove  the  platinum  from  the  iron. 
The  latter  is  then  dissolved  off  the  filter  with  HC1  and  finished  as 
given  for  iron  ore. 

Manganese  is  gotten  in  the  same  manner  as  for  manganese 
in  insoluble  ferro- titanium.  (See  page  52.) 

TYPICAL  ANALYSES. 


No.  i. 

No.  2. 

Iron 

70-44 

78.16 

Mtangcinese 

0.05 

0.06 

Phosphorus                             

18.51 

20.45 

Sulphur                     

0.67 

0.55 

Silicon 

0.76 

0.54 

Carbon                                   

0.26 

o.  16 

CHAPTER  XII. 


PART  IV. 

SULPHUR  IN  STEEL,  MUCK  BAR,  PIG  IRON  AND  WASHED 

METAL. 

VOLUMETRIC. 

DISSOLVE  three  grams  of  sample  in  70  c.c.  of  i  :  i*  hydro- 
chloric  acid.     More   than   this   amount  of  acid  is   sometimes 
required  for  rapid  solution.     The  dissolving  flask  is  the  author's 
design  and  is  made  in  a  mold  with  a  fire  fin- 
ish, ring  neck.     The  flask,  being  made  in  a 
mold  instead  of  by  hand,  has  a  perfectly 
round  neck  and  always  takes  a  No.  6  rub- 
ber   stopper.      Its   capacity  is   275   c.c.   to 
base  of  neck,  and  its  height  is  165  mm.     It 
is  a  great  convenience  to  have  these  details 
always  the   same.      (Fig.  4.)      Previous  to 
designing  this  flask  much  trouble  was  exper- 
ienced in  different  lots   of  flasks.      In  the 
same  lot  some  would  require  a  No.  4,  others 
a  No.  5,  and  some  a  No.  6  stopper  to  get  a 
good  fit.    Then  ground  finish  flasks  will  crack 
at  the  neck  when  placed  in  the  heater  to 
dry   out    the   water.      Drillings    are    never 
weighed  into  wet  flasks.    The  No.  6  stopper  is  perforated  with 
three  holes,  one  to  receive  a  bulb  funnel  of  75  c.c.  capacity. 
This  funnel  is  also  designed  to  facilitate  the  work.     It  has  an 
opening  at  the  top  of  the  bulb  of  15  mm.  diameter.     The  glass 
cock  has  an  extra  large  hole  bored  in  it  (3^  mm.  diameter)  to 

*  2  parts  of  1.20  HC1  (cone.)  to  i  part  of  water  are  more  reliable  as  some  kinds 
of  pig  iron  show  no  sulphur  at  all  by  the  evolution  method  with  weaker  acid. 

269 


FIG.  19. 


270  CHEMICAL  ANALYSIS   OF  SPECIAL   STEELS 

permit  of  rapid  flow  of  the  acid  from  the  bulb  into  the  flask. 
The  total  distance  from  the  base  of  the  bulb  to  the  outlet  in 
the  stem  is  145  mm.  The  second  hole  in  the  stopper  admits 
a  small  tube  that  dips  just  below  the  level  of  the  fluid  in  flask. 
After  the  iron  is  completely  dissolved,  hydrogen  is  forced  through 
this  inlet  for  from  three  to  five  minutes  to  drive  out  any  hydrogen 
sulphide  that  may  remain  in  the  interior  of  the  flask.  The 
third  hole  admits  the  delivery  tube  which  carries  the  evolved 
gases  to  the  bottom  of  the  absorbing  solution  of  ammoniacal 
cadmium  chloride.  This  solution  is  contained  in  a  thick  wall, 
thick  bottom,  test  tube  about  10  inches  by  i  inch.  Fifty  c.c. 
of  the  solution  are  used  for  each  analysis. 

The  flask  is  clamped  in  a  rack  supporting  four  flasks  to  .the 
stand.*  Each  stand  is  supplied  with  four  burners.  The  top  of 
the  stand  on  which  the  bottoms  of  the  flasks  rest  is  an  asbestos 
copper-rimmed  board  with  a  circular  hole  of  42  mm.  diameter  cut 
in  it  immediately  over  each  burner.  The  bottom  of  the  flask 
rests  in  this  hole.  Ranged  alongside  of  this  rack  is  a  wooden 
one  holding  the  four  absorption  tubes.  As  many  such  sets  of 
four  are  in  operation  at  one  time  as  the  chemist  can  manage.* 

When  the  solutions  no  longer  evolve  gas  to  any  extent  without 
the  aid  of  heat,  the  flames  are  raised  slightly  so  'as  to  maintain 
a  very  slight  boiling  action.  When  heat  no  longer  produces 
gas  bubbles  in  the  absorption  tubes,  the  hydrogen  is  turned  in 
and  a  rather  rapid  passage  of  this  gas  is  continued  for  from  three 
to  five  minutes.  The  cocks  on  all  of  the  bulb  funnels  are  then 
opened.  The  hydrogen  is  shut  off  at  each  flask. 

The  cadmium  solution  containing  the  precipitate  of  sulphide 
is  poured  on  a  rapid  running  No.  597,  u  cm.  S.  &  S.  filter.  The 
absorption  tube  is  rinsed  with  water  and  the  washings  are 
poured  on  the  filter.  The  latter  is  washed  three  or  four  times 
with  water.  The  delivery  tube,  if  much  precipitate  adheres 
to  it,  is  cleansed  by  rubbing  it  with  a  little  filter  paper.  This 
small  piece  of  paper  is  then  dropped  in  on  the  main  portion  of 
the  cadmium  sulphide  to  which  it  belongs.  The  delivery  tube 
*  See  Fig.  2,  page  104. 


SULPHUR  IN   STEEL,  MUCK   BAR,  PIG   IRON,  ETC.         271 

without  further  washing  is  put  back  into  its  respective  absorption 
tube. 

Both  tubes  together  with  the  filter  paper  containing  the 
major  part  of  the  sulphide  are  taken  to  the  titration  table 
together  with  the  other  tests  which  have  been  similarly  pre- 
pared. The  filter  paper  with  the  adhering  sulphide  is  placed 
in  a  1000  c.c.  beaker  containing  500  c.c.  of  water.  For  con- 
venience the  beaker  should  have  an  etched  mark  on  it  to  indicate 
the  half  liter. 

The  paper  is  beaten  into  fragments  with  a  glass  rod  and 
the  pulp  is  stirred  all  through  the  water.  Two  c.c.  of  starch 
solution  are  added.  The  absorption  tube  corresponding  to 
this  filter  is  filled  one-quarter  full  of  distilled  water  and  then 
to  within  an  inch  of  the  top  with  i  :  i  hydrochloric  acid.  Fur- 
ther, the  delivery  tube,  which  has  been  momentarily  removed 
from  the  absorption  tube  previous  to  adding  the  water,  is  re- 
turned to  the  acid  fluid,  and  is  raised  and  lowered  in  it  to  dis- 
solve any  small  quantity  of  cadmium  sulphide  adhering  to  its 
interior  or  exterior  walls.  It  is  then  laid  aside  and  the  fluid  in 
the  absorption  tube  is  poured  into  the  water  containing  the 
bulk  of  the  yellow  sulphide.  This  acid  is  not  dumped  in  pro- 
miscuously but  is  allowed  to  run  down  the  inner  wall  of  the 
beaker  rather  slowly  so  as  not  to  disturb  the  contents  thereof. 
Before  stirring  the  acid  through  the  latter,  iodine  is  dropped 
in  from  a  Gay-Lussac  burette  held  in  the  operator's  left  hand. 
The  drops  are  added  in  such  a  way  that  a  circle  of  drops  extends 
around  the  inner  circumference  of  the  beaker.  With  his  other 
hand  the  operator  now  gives  the  solution  in  the  beaker  a  slight 
stir  with  a  glass  rod.  If  this  causes  the  blue  to  disappear,  leaving 
a  reddish  tint,  another  circle  of  drops  of  iodine  is  added,  and  so 
on  until  two  or  three  drops  of  the  standard  iodine  solution 
produce  a  purplish  blue  end  point  which  does  not  fade  to  a  red 
with  more  stirring. 

The  number  of  c.c.  of  iodine  used  less  the  number  of  c.c. 
required  to  produce  a  faint  blue  in  a  blank  test,  multiplied  by 
the  percentage  value  in  sulphur  of  the  iodine  standard,  equals 


272  CHEMICAL  ANALYSIS  OF   SPECIAL   STEELS 

the  per  cent  of  sulphur.  The  blank  test  is  made  on  the  same 
amounts  of  starch,  filter  paper  and  water  as  are  used  in  an 
actual  analysis. 

This  sulphur  value  is  obtained  by  running  steels  of  known 
sulphur  content  in  the  manner  described. 

The  U.  S.  Bureau  of  Standards,  Washington,  D.  C.,  also 
furnishes  phosphorus,  sulphur,  silicon  and  manganese  stand- 
ards for  pig  iron  and  steel  that  have  been  analyzed  by  chemists 
experienced  in  iron  and  steel  analysis.  These  constitute  a 
valuable  aid  to  the  analyst,  enabling  him  at  any  time  to  check 
his  own  standards.  The  cost  of  these  standards  is  low.  Steps 
are  being  taken  with  a  view  to  preparing  also  a  series  of  various 
alloy  steel  standards  standardized  as  to  vanadium,  titanium, 
chromium,  tungsten  and  molybdenum  content.* 

Each  day  a  standard  steel  should  be  run  with  the  other  work, 
as  new  acids  and  chemicals  are  liable  to  cause  the  sulphur  value 
of  the  iodine  to  change  from  that  originally  obtained  when  it 
was  first  standardized. 

This  method  is  accurate  for  all  unhardened  plain  carbon 
steels,  and  for  annealed  pig  iron  and  for  muck  bar.  In  chilled 
pig  iron,  unless  first  annealed,  the  results  are  usually  about 
25  per  cent  lower  than  the  actual  sulphur,  and  yet,  in  spite  of 
this  fact,  by  reason  of  its  rapidity,  practically  the  method  as 
given  is  very  generally  in  use  by  buyer  and  seller  of  pig  iron. 
The  practice  of  annealing  the  drillings  in  covered  crucibles,  at  a 
red  heat,  for  15  minutes,  may  probably  come  into  vogue. 

However,  if  the  buyer  and  seller  understand  the  limitations 
of  the  method  it  would  seem  unnecessary  to  resort  to  this  detail. 
The  steel  furnace  superintendent  could  calculate  his  sulphur 
content  one-fourth  higher  than  the  laboratory  report.  Or  the 
buyer  and  the  seller  could  agree  that  if  their  respective  labora- 
tories find  0.060  per  cent  sulphur,  for  example,  in  pig  iron,  it 
shall  be  reported  as  0.075  Per  cent,  thus  saving  valuable  time  in 

*  As  is  generally  known  the  U.  S.  Bureau  of  Standards  now  has  plain  vana- 
dium, chrome-vanadium,  chrome-nickel,  chrome  tungsten  and  plain  nickel  stand- 
ards for  distribution  at  a  reasonable  rate. 


SULPHUR  IN  STEEL,  MUCK  BAR,   PIG  IRON,  ETC.         273 

the  laboratory  and  yet  have  records  that  are  sufficiently  close  to 
the  truth  for  all  practical  purposes. 

The  evolution  method  is  unreliable  for  steels  high  in  copper 
and  for  many  alloy  steels  that  form  carbides  that  are  insoluble 
in  i  :  i  hydrochloric  acid.  The  results  are  too  low.  (See 
analysis  of  these  steels.*) 

THE  STARCH  SOLUTION. 

Grind  i  gram  of  good  wheat  starch,  free  from  rancid  smell, 
to  a  powder.  Stir  it  with  10  c.c.  of  water  in  a  small  beaker 
and  put  it  carefully  into  90  c.c.  of  boiling  water.  Cool  and  use 
as  needed.  It  is  best  to  prepare  this  solution  daily. 

IODINE  STANDARD.! 

One  gram  of  best  resublimed  iodine  is  dissolved  in  a  very 
little  water  together  with  10  grams  of  c.p.  potassium  iodide. 
This  is  diluted  to  1000  c.c.  with  distilled  water.  It  is  stand- 
ardized against  a  steel  of  known  sulphur  content. 

CADMIUM  CHLORIDE  SOLUTION. 

Twenty  grams  of  anhydrous  cadmium  chloride  are  dissolved 
in  1400  c.c.  of  ammonia  water  of  0.9  specific  gravity.  This 
solution  is  diluted  to  4  liters  with  distilled  water  for  use. 

LEAD  ACETATE  SOLUTION. 

For  purification  of  the  hydrogen  before  it  enters  the  sulphur 
flasks,  it  is  allowed  to  bubble  through  a  500  c.c.  Bunsen  wash 
bottle  containing  a  solution  of  lead  acetate  made  as  follows: 

(1)  Dissolve  100  grams  of  lead  acetate  in  400  c.c.  of  water. 

(2)  Dissolve  400  grams  of  potassium  hydroxide  in  500  c.c.  of 
water.     Pour  one  solution  into  the  other  and  mix  thoroughly. 
Use  1 20  c.c.  of  this  solution  in  each  wash  bottle. 

The  hydrogen  is  generated  in  an  ordinary  Kypp  apparatus. 

*  Read  pages  102  and  104. 

t  One  c.c.  of  this  standard  equals  from  about  0.0042  to  0.0045  per  cent  of 
sulphur  when  3  grams  of  sample  are  taken  for  analysis. 


274  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

GRAVIMETRIC  SULPHUR  IN  PIG  IRON,  STEEL,  WASHED 
METAL  AND  MUCK  BAR. 

Dissolve  5  grams  of  drillings  of  0.04  per  cent  and  higher 
sulphur  content  in  200  c.c.  concentrated  nitric  acid,  using  an 
800  c.c.  beaker.  For  percentages  of  sulphur  under  0.04  per  cent 
use  10  gra'ms  of  drillings,  dissolving  the  latter  in  300  c.c.  of  con- 
centrated nitric  acid.  Add  the  nitric  acid  a  few  c.c.  at  a  time, 
as  the  reaction  is  violent.  When  all  acid  is  in  the  beaker,  warm 
the  contents  of  same  until  action  is  over.  Then  add  2  grams 
of  sodium  carbonate.  Transfer  the  solution  to  a  No.  6  dish 
and  evaporate  on  the  sand  or  graphite  bath  to  dryness.  Dis- 
solve in  100  c.c.  of  i.  20  hydrochloric  acid,  keeping  the  dish 
covered  until  spraying  ceases.  Remove  the  cover  and  evap- 
orate to  dryness  again.  Dissolve  once  more  with  50  c.c.  con- 
centrated HC1  and  evaporate  to  a  scum.  Add  10  c.c.  of 
concentrated  hydrochloric  acid,  or  more  if  necessary,  and  heat 
with  cover  on  until  all  iron  is  in  solution.  Add  100  c.c.  of  water. 
Filter;  wash  with  dilute  HC1  (i  :  20).  Dilute  the  filtrate 
and  washings  to  400  c.c.  Heat  to  boiling.  Add  60  c.c.  of  a 
saturated  solution  of  barium  chloride,  diluted  with  200  c.c.  of 
water.  Filter  the  barium  chloride  before  using  it.  Stir  the 
solution  thoroughly  after  adding  the  barium  chloride.  After 
twelve  hours  filter  the  precipitated  barium  sulphate  on  a  double 
9  cm.  ashless  filter.  Barium  sulphate  is  quite  soluble,  even  in 
very  dilute  hydrochloric  acid.  It  should  be  washed  free  from 
iron  with  cold  water  and  only  an  occasional  washing  with  water 
containing  one  or  two  drops  of  i  :  i  hydrochloric  acid  in  100  c.c. 
of  distilled  water. 

Wash  about  every  fifth  time  with  this  acidulated  water 
until  no  iron  test  is  obtained  with  KCNS  and  then  free  from 
chloride  test  with  water  alone.  Ignite  in  a  weighed  platinum 
crucible.  Add  one  or  two  drops  of  i  :  3  sulphuric  acid  and 
ignite  again.  Weigh  as  BaS04.  Obtain  a  blank  in  the  same 
Way.  Deduct  the  BaSO4  found  in  the  blank  and  multiply  the 
remainder  by  13.73  and  divide  the  product  by  the  weight  taken 


SULPHUR  IN   STEEL,  MUCK   BAR,  PIG   IRON,   ETC.        275 

for  analysis  to  obtain  per  cent  of  sulphur.  If  the  barium  sulphate 
does  not  burn  white  it  can  be  fused  with  i  gram  of  sodium 
carbonate.  The  melt  is  then  dissolved  in  water;  filtered  from 
BaCO3;  the  filter  washed  with  water  and  the  filtrate  and  wash- 
ings acidulated  with  a  slight  excess  of  i  :  i  hydrochloric  acid. 
Heat  to  boiling  and  precipitate  with  10  c.c.  of  a  filtered,  satu- 
rated solution  of  barium  chloride  diluted  to  50  c.c.  with  water. 
Finish  as  before,  washing  this  time  with  water  only. 


CHAPTER  XII. 


PART  V. 

MANGANESE  IN  PIG  IRON,  TUNGSTEN  STEEL,  MUCK  BAR, 

NICKEL  STEEL,  MOLYBDENUM  STEEL,  VANADIUM 

STEEL,  TITANIUM  STEEL  AND  CHROME  STEEL. 

FOR  pig  iron,  muck  iron,  plain  carbon  or  plain  vanadium  steel 

or  nickel  steel,  titanium  steel  with 
absence  of  chromium  and  with  sili- 
con not  over  i  per  cent,  and  tung- 
sten steel  not  over  3.5  per  cent 
tungsten,  accurate  to  2  per  cent  of 
manganese.  Dissolve  o.  100  gram  for 
manganese  of  not  over  i  per  cent 
manganese  or  0.050  gram  for  higher 
percentages  in  40  c.c.  i.2ojiitric  acid 
in  a  10  by  i  inch  test  tube  over  a 
low  Bunsen  flame.  (See  Fig.  20.) 
Boil  until  red  fumes  are  gone. 
Revolve  the  tubes  from  over  the 
flame  and  add  cautiously  3  grams 
of  light  brown  colored  peroxide  of 
lead  free  from  manganese.  Do  not 
use  lead  peroxide  of  the  very  dark 
brown,  in  some  instances,  almost 
&.  black  color,  as  this  very  dense  vari- 
ety does  not  yield  its  oxygen  read- 
ily, and  results  will  not  check  and 
are  frequently  25  per  cent  too  low. 
Insist  on  getting  light  brown  lead 
peroxide.* 


FIG.  20. 
Manganese  in  steel. 


Fig.  20  is  after  a  design  by  Dr.  E.  S.  Johnson. 
276 


MANGANESE  IN  PIG  IRON,  TUNGSTEN  STEEL,  MUCK  BAR,  ETC.  277 

After  adding  the  lead  to  all  of  the  tubes,  raise  the  flames 
causing  the  contents  to  boil  almost  to  the  top  of  the  test  tubes, 
four  minutes.  Lower  the  flames,  place  the  tubes  quickly  in 
cool  water,  and  then,  after  a  few  seconds'  delay,  directly  into 
cold  water.  Permit  the  excess  of  lead  peroxide  to  settle  ten 
minutes,  or  longer  if  convenient,  in  a  dark  cupboard. 

Decant  the  contents  of  the  tubes  into  5  ounce  beakers  as 
needed,  leaving  all  black  sediment  in  the  bottom  of  the  test 
tube.  Titrate  the  pink  solution  with  standard  sodium  arsenite 
until  all  pink  or  brown  shades  are  gone  and  a  suggestion  of 
yellow  color  appears.  The  writer  has  tried  many  methods  for 
the  quick  determination  of  manganese,  and  can  recommend  it  in 
preference  to  other  methods  for  simplicity,  speed  and  accuracy. 
Chromium  is  about  the  only  disturbing  element  likely  to  be  met 
with  in  steels,  and  can  be  quickly  removed  by  the  following 
method,  which  is  used  also  for  all  high-speed  combinations  and 
high  per  cent  tungsten  steels: 

Dissolve  0.300  gram  or  0.150  gram  in  low  and  high  man- 
ganese steels,  respectively,  and  proceed  exactly  as  given  for  the 
determination  of  manganese  in  chrome- vanadium  steels.  (See 
Analysis  of  Vanadium  Steels,  page  15.) 

For  plain  molybdenum  steels  without  chromium,  proceed 
as  in  plain  steels.  Presence  of  large  quantities  of  copper  and 
nickel  do  not  interfere  with  this  method.  Of  course,  hydro- 
chloric acid  should  be  absent,  or  any  other  substance  that 
would  reduce  permanganic  acid,  such  as  carbonaceous  materials. 
Sunlight  bleaches  the  pink  color,  causing  low  results. 

For  the  determination  of  manganese  in  cobalt  steels,  see  page  321. 

STANDARD  SODIUM  ARSENITE  SOLUTION.* 

Concentrated  Stock  Solution.  2.48  grams  of  c.p.  arsenious 
acid  and  12.5  grams  of  c.p.  fused  sodium  carbonate  dissolved 
in  1250  c.c.  of  distilled  water.  Dissolve  the  arsenious  acid  and 
the  carbonate,  at  first,  in  a  little  hot  water. 

*  Deshay  suggested  the  sodium  arsenite  titration. 


278  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Working  Strength.  200  c.c.  of  stock  solution  diluted  with 
1600  c.c.  of  water.  One  c.c.  of  this  solution  will  equal,  usually, 
0.07  per  cent  of  manganese  when  o.ioo  gram  of  sample  is  taken. 
It  should  be  checked  against  steels  of  known  manganese  content 
before  it  is  used.  . 

THE  AUTHOR'S  MODIFICATION  OF  THE  PERSULPHATE  AND 
LEAD  PEROXIDE  METHODS  FOR  MANGANESE  IN 
EXCESS  OF  2  PER  CENT. 

The  author  has  tested  the  following  schemes  for  manganese 
up  to  15  per  cent: 

By  lead  peroxide:  Dissolve  o.ioo  gram  of  the  steel  in  350  c.c. 
of  i. 20  nitric  acid  in  the  style  of  flask  shown  on  page  269  and  of 
500  c.c.  capacity.  Boil  the  solution  on  the  Argand  heater  shown 
on  page  258  for  20  minutes,  keeping  the  flask  covered  with  a  i 
inch  watch  glass,  and  boiling  gently.  Add  a  little  precipitated 
silica  before  starting  to  boil  to  prevent  uneven  boiling.  Remove 
the  flask  from  the  fire  and  add  10  grams  of  the  light  brown  lead 
peroxide.  Put  back  on  the  heater  and  boil  quietly  for  5  minutes. 
Cool  the  flask  in  running  water  and  permit  the  lead  to  settle  for 
at  least  3  hours.  Decant  the  deep  purple  supernatent  fluid  into 
a  400  c.c.  beaker,  taking  great  care  not  to  pour  off  any  of  the  lead 
oxide  lying  in  the  bottom  of  the  flask.  Add  to  the  decanted 
liquor  a  standard  solution  of  ferrous  ammonium  sulphate  until 
all  pink  and  brown  tints  are  gone  from  the  test  and  the  liquid  has 
an  almost  water  white  appearance.  Now  titrate  back  with  a 
standard  solution  of  potassium  permanganate  until  one  or  two 
drops  of  the  latter  render  the  test  the  faintest  pink.  Then  add 
the  sulphate  standard  again  until  this  faint  pink  is  changed  to 
almost  water  white.  Use  100  c.c.  burettes  and  avoid  a  large 
excess  of  the  sulphate. 

CALCULATIONS  AND  STANDARDS. 

The  permanganate  standard  is  made  by  dissolving  0.560  gram 
of  KMnC>4  c.p.  in  water  and  diluting  to  i  liter. 

The  sulphate  standard  is  made  by  dissolving  13.7  grams  of  c.p. 
ferrous  ammonium  sulphate  in  water  and  diluting  to  2  liters. 


MANGANESE  IN  PIG  IRON,  TUNGSTEN  STEEL,  MUCK  BAR,  ETC.  279 

i  c.c.  of  this  standard  should  equal  from  0.000195  to  0.000198 
gram  of  metallic  manganese.  Standardize  either  with  a  similar 
steel  which  has  been  carefully  determined  either  by  the  method 
given  on  pages  188,  193,  or  201,  or  add  0.050  gram  of  c.p.  KMn04 
to  a  low  manganese  steel  containing,  for  example,  0.23  per  cent 
of  manganese,  and  put  it  through  all  of  the  operations.  Such  a 
mixture  will  contain  0.050  X  0.3476  or  0.01738  gram  of  Mn  from 
the  KMn04  and  0.00023  gram  of  Mn  from  the  o.ioo  gram  of  steel, 
making  a  total  of  0.0176  gram  of  Mn.  The  mixture  should 
require  from  89.8  to  90.6  c.c.  of  the  sulphate  standard  if  the 
directions  are  carried  out  exactly  as  given. 

If  the  steel  contains  chromium  it  must  be  dissolved  in  i  :  3 
sulphuric  acid  and  the  chromium  removed  with  zinc  oxide. 
Dissolve  i  gram  in  50  c.c.  of  i  :  3  HgSC^  in  a  500  c.c.  volumetric 
flask,  boil  with  40  c.c.  1.20  HNO3,'  dilute  to  300  c.c.,  add  a 
slight  excess  of  the  zinc  oxide,  dilute  to  the  mark,  mix  well,  filter 
through  a  dry  filter,  fill  a  100  c.c.  burette  with  the  filtrate  and 
measure  50  c.c.  into  the  500  c.c.  flask,  add  350  c.c.  of  1.20  nitric 
acid  and  finish  as  above.  Put  the  above  standardizing  mixture 
through  the  same  operations,  including  enough  potassium  di- 
chromate  to  equal  the  chromium  content  of  the  test. 

The  persulphate  method:  Dissolve  o.ioo  gram  of  the  sample  in 
a  liter  boiling  flask  in  250  c.c.  of  i  :  3  sulphuric  acid  and  then  add 
100  c.c.  of  i. 20  nitric  acid  and  boil  gently  20  minutes.  Remove 
from  the  heat  and  add  150  c.c.  of  silver  nitrate  solution  (10  grams 
dissolved  in  a  liter  of  water).  Next  add  200  c.c.  of  persulphate 
of  ammonium  (480  grams  dissolved  in  2  liters).  Place  again  on 
the  stove  and  heat  at  about  60°  C.  until  all  frothing  is  over 
and  until  practically  no  more  fine  bubbles  continue  to  form  in 
the  solution.  This  will  require  about  45  minutes  heating  at  the 
above  temperature.  Cool  in  running  water  and  titrate  the 
purple  solution  with  the  same  standards  as  given  in  the  similar 
lead  peroxide  method.  Titrate  cold.  Separate  chromium  if 
present  as  in  the  lead  peroxide  method.  The  sulphate  stand- 
ard has  the  same  value  in  metallic  manganese  as  in  the  latter 
method. 


280 


CHEMICAL  ANALYSIS   OF  SPECIAL  STEELS 


Sample. 

Phosphate. 

Results  by  the  different  methods. 

Lead  peroxide. 

Persulphate. 

No. 
40 

Mn 
14.84 

14.76 
14.92 

14.85 
14-77 

39 

9.04 

9.09 
9.10 

9-03 
9.II 

NOTE.    Titration  with  arsenious  acid  is  objectionable  in  such  high  per  cents  of 
Mn  as  it  gives  brown  tints  that  obscure  the  end  point. 


CHAPTER  XII. 

PART  VI. 

THE  DETERMINATION  OF  MANGANESE  IN  24  PER  CENT 

NICKEL  STEEL  CONTAINING  MANGANESE  IN 

EXCESS  OF  TWO  PER  CENT. 

THE  ferricyanide  method  cannot  be  used  on  account  of  the 
interference  of  the  nickel.  Dissolve  i.o  and  0.9  gram  for  a 
check  in  50  c.c.  of  1.20  nitric  acid.  Rinse  the  solution  into 
a  liter  volumetric  flask;  add  25  c.c.  additional  to  insure  a  large 
excess  of  acid.  Add  a  thick  cream  of  manganese-free  zinc  oxide 
to  the  solution  which  has  been  diluted  beforehand  to  500  c.c. 
with  water.  Add  the  oxide  rather  slowly  until  the  hydroxide 
of  iron  separates  out,  mixing  the  contents  of  the  flask  well  with 
each  addition  of  the  oxide,  by  giving  the  flask  a  swirling  motion. 
In  order  to  be  certain  that  the  oxide  is  in  excess,  the  separated 
precipitate  should  have  a  light  brown  to  whitish  brown  appear- 
ance rather  than  a  dark  red.  The  contents  of  the  flask  are  then 
diluted  to  the  mark  and  all  is  then  mixed  by  inverting  the  flask 
5  times.  Permit  the  precipitate  to  settle  and  then  decant  the 
supernatant  fluid  through  a  dry  15  c.c.  filter  into  a  dry  beaker. 
By  means  of  a  100  c.c.  burette  that  has  been  rinsed  three  times 
with  some  of  the  filtered  solution,  measure  off  a  500  c.c.  and  a 
250  c.c.  portion  of  the  filtered  solution  into  1000  c.c.  boiling 
flasks,  and  titrate  the  aliquot  parts  in  the  manner  described  on 
page  49,  using  a  permanganate  standard  of  which  i  c.c.  equals 
about  o.ooi  gram  of  manganese.  When  making  these  titra- 
tions  with  such  a  weak  standard  the  operator  may  be  uncertain 
as  to  the  end  point,  as  small  particles  of  manganese  hydrate 
that  are  held  in  suspension  may  give  a  pinkish  effect  to  the 
supernatent  fluid  during  the  titration.  It  is  therefore  best  to 
filter  off  a  few  drops  of  the  pinkish  appearing  fluid  through 

281 


282  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

washed  asbestos  that  has  been  previously  boiled  with  some 
rather  concentrated  permanganate  solution  and  afterwards 
washed  free  of  pink  color.  The  asbestos  so  prepared  will  not 
bleach  a  few  drops  of  even  a  very  slightly  pink  test. 

STANDARDIZATION. 

Dissolve  and  put  through  all  of  the  above  operations  the 
following  known  mixtures:  (i)  0.9  gram  of  iron  containing  no 
manganese,  or  a  small  known  amount,  1.5  gram  of  the  double 
sulphate  of  nickel  and  ammonium,  and  0.140  gram  of  the  purest 
permanganese  of  potassium;  (2)  i.o  gram  of  manganese -free 
iron,  i. 60  gram  of  the  nickel  salt  and  0.150  gram  of  the  per- 
manganate. Mixture  (i),  assuming  the  full  value  of  the  per- 
manganate to  be  present,  should  contain  0.140  X  0.34759  or 
0.04866  gram  of  manganese.  As  500  c.c.  were  measured,  or 
one-half,  then  0.02433  gram  of  metallic  manganese  was  titrated; 
this  required  25.8  c.c.  of  the  standard  to  produce  a  permanent 
pink;  therefore  0.02433  divided  by  25.8  equals  0.00094,  or  i  c.c. 
of  the  standard  equals  0.00094  gram  of  metallic  manganese.  By 
the  same  process  (2)  gave  a  value  of  i  c.c.  equals  0.00104  gram 
of  manganese.  The  average  of  the  two  gives  i  c.c.  equals 
0.06099  gram  of  manganese. 


CHAPTER  XII. 

PART  VII. 

DETERMINATION  OF  MANGANESE  IN  STEEL  BY  THE 
PERSULPHATE  METHOD. 

THE  use  of  ammonium  persulphate  and  silver  nitrate  for  the 
determination  of  manganese  in  steel  was  first  worked  out  in  the 
United  States  by  Walters.  Ledebur  in  his  Leitfaden  fur  Eisen- 
hutten  Laboratorien  refers  to  it  as  the  method  of  Proctor  Smith. 
The  silver  nitrate  acts  as  an  oxygen  carrier  by  the  intermediate 
formation  of  silver  peroxide.  The  equations  showing  the  action 
of  the  persulphate  and  the  arsenious  acid  and  the  permanganic 
acid  are  given  below: 

2  Mn(N03)2  +  5  (NH4)2S208  +  8  H2O  =  2  HMn04  -f-         (i) 


4  HMn04  +  10  As(OH)3  +  8  HNO3  =  10  HsAs04  +          (2) 
4  Mn(N03)2  +  6  H2O. 

Ledebur  proceeds  as  follows:  "0.2  gram  of  iron  is  dissolved 
in  a  beaker,  in  15  c.c.  of  sulphuric  acid  (i  part  of  concentrated 
acid  diluted  with  2  parts  of  water)  to  which  has  been  added 
3  c.c.  of  1.20  nitric  acid.  In  the  case  of  grey  iron  the  graphite 
is  filtered  out  and  the  filter  is  washed  a  number  of  times  with 
water  containing  a  drop  or  two  of  sulphuric  acid.  (The  author 
suggests  the  dilute  sulphuric  wash  as  Ledebur  does  not  specify 
the  kind  of  a  wash  to  use.)  As  a  conveyor  of  oxygen,  10  c.c.  of 
silver  nitrate  solution  (5  grams  of  the  silver  salt  dissolved  in  a 
liter  of  water)  are  added  to  the  sulphuric  acid  solution  of  the 
iron  and  thereupon  15  c.c.  of  ammonium  persulphate  made  by 
dissolving  60  grams  of  the  persulphate  in  a  liter  of  water." 

"  The  solution  of  the  sample  is  then  heated  as  long  as  gas  bub- 
bles form  in  the  same  and  until  the  last  traces  of  persulphate  are 

283 


284  CHEMICAL  ANALYSIS  OF  SPECIAL^ STEELS 

decomposed.  This  can  be  usually  accomplished  by  heating 
over  a  Bunsen  burner  for  a  minute.  The  careful  adhering  to 
these  directions  is  important  as  it  is  easy  to  get  too  high  results, 
if  the  persulphate  is  imperfectly  decomposed,  in  that  during  the 
titration  with  arsenious  acid  a  partial  reoxidation  of  the  reduced 
manganese  salt  or  a  slight  reaction  of  the  persulphate  with  the 
arsenious  acid  may  occur." 

"  If  during  the  oxidation  of  the  manganese  solution  no  red  color 
forms  then  the  solution  is  not  sufficiently  dilute.  One  can  then 
add  20  c.c.  of  water,  a  further  quantity  of  the  persulphate  and 
heat  again.  The  heating  should  not  exceed  60°  C.  at  any  time 
during  the  treatment  with  silver  nitrate  and  persulphate." 

The  writer  would  suggest  that  the  above  directions  which  he 
has  translated  from  Ledebur  would  have  to  be  deviated  from  to 
suit  the  case  as  regards  the  amount  of  sample  taken,  for  instance 
it  would  not  be  advisable  to  take  0.2  gram  of  a  steel  containing 
2  or  3  per  cent  of  manganese.  In  such  high  per  cents  from  o.i 
to  0.05  gram  would  be  quite  enough  to  insure  accuracy. 

Ledebur  titrates  the  cold  solution,  after  diluting  it  with  50 
c.c.  of  water,  with  a  solution  of  arsenious  anhydride  made  by 
dissolving  0.4  gram  of  the  finely  powdered  oxide  by  warming  it 
with  1.5  gram  of  anhydrous  sodium  carbonate  dissolved  in  a 
little  water.  When  the  arsenious  anhydride  is  dissolved  it  is 
diluted  to  one  liter. 


CHAPTER  XII. 

PART  VIII. 
SILICON  IN  PIG  IRON,  STEEL  AND  MUCK  BAR. 

WEIGH  1.5  grams  of  pig  iron  into  a  No.  2  dish.  Add  15  c.c. 
i  :  3  sulphuric  acid  *  plus  10  c.c.  water.  Weigh  5  grams  of  low 
silicon  steel  or  3  grams  of  high  silicon  steel,  i.e.,  silicon  content 
of  o.i  per  cent  and  over,  into  a  No.  5  dish.  Add  45  c.c.  i  :  3 
sulphuric  acid  and  25  c.c.  of  water.  Warm  gently  until  all 
metal  is  in  solution,  adding  more  water  if  necessary,  should 
sulphate  of  iron  form  before  effervescence  is  over.  When  the 
iron  is  in  solution  evaporate  the  pig  iron  and  higher  carbon  steels 
directly  to  thick  fumes  of  sulphuric  anhydride  without  removing 
the  covers. 

Low  carbon  steels  and  chrome  steels  of  i  per  cent  chromium 
and  over  will  bump  and  spurt  from  under  the  covers  if  attempt 
be  made  to  evaporate  them  rapidly  over  the  bare  flame  of  the 
Argand  burner.  In  such  cases  the  covers  are  rinsed  off  into  the 
dishes,  and  the  contents  of  the  latter  are  evaporated  to  thick 
fumes  on  a  graphite  or  sand  bath.  (See  page  415.) 

For  effecting  the  solution  of  the  iron  and  the  evaporation  of 
fumes  with  covers  on,  an  apparatus  consisting  of  a  stand  of 
twelve  Argand  burners  covered  with  a  copper-rimmed  asbestos 
board  of  twelve  holes  is  used.  (See  Fig.  16,  page  258.) 

Having  evaporated  the  samples  to  fumes,  the  dishes  are  cooled 
and  filled  conveniently  full  of  distilled  water.  They  are  put 
on  the  heating  stand;  the  contents  heated  and  stirred  until  all 
of  the  sulphate  of  iron  is  in  solution.  Ashless  paper  pulp  is 
mixed  with  the  solutions,  which  are  then  filtered  through  n 

*  Use  rubber  stoppers  in  reagent  bottles  that  are  in  constant  use  in  routine 
silicon  work,  as  during  continued  handling  the  glass  stoppers  are  struck  against 
the  necks  of  the  bottles  and  small  chips  of  glass  are  knocked  off  into  the  acids 
causing  high  results. 

285 


286  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

cm.  ashless  filters;  the  silicious  residues  washed  free  from  iron 
test  with  i  :  10  hydrochloric  acid  and  then  free  of  acid  with 
water.  Potassium  sulphocyanate  is  used  in  testing  for  the  pres- 
ence of  iron.  Wash  acid  and  wash  water  are  applied  cold. 

The  washed  residues  are  ignited  in  a  muffle  furnace  until  pure 
white.*  The  residues  may  retain  a  reddish  tint  due  to  iron,  or 
may  be  colored  grey  from  presence  of  chromium  or  copper  oxides, 
or  yellow  owing  to  the  presence  of  small  quantities  of  tungsten 
or  vanadium.  In  such  event  after  having  been  weighed  they 
should  be  evaporated  to  dryness  with  a  few  drops  of  sulphuric 
acid  and  10  c.c.  of  c.p.  hydrofluoric  acid.  They  are  then  ignited 
and  weighed  again,  and  the  silicon  content  is  calculated  from 
the  loss  of  weight,  which  multiplied  by  47.02  and  divided  by 
the  weight  taken,  yields  the  percentage  of  silicon. 

When  chromium  is  present,  to  the  extent  of  i  per  cent,  the 
silica  residue  can  be  freed  sufficiently  from  chromium  to  make 
a  subsequent  evaporation  with  hydrofluoric  and  sulphuric  acids 
unnecessary  by  boiling  the  fumed  sulphate  residue  for  ten  min- 
utes with  a  mixture  of  75  c.c.  of  i  :  i  hydrochloric  acid  and  75 
c.c.  of  water.  Then  filter  and  wash  as  before.f 

The  ignited  residues  are  cooled  in  a  desiccator,  weighed,  mul- 
tiplied by  47.02  and  divided  by  the  weight  taken. 

The  silicious  residues  obtained  by  this  method,  or  any  other 
of  the  variations  that  are  in  vogue,  are  liable  to  be  contami- 
nated with  titanium  and  aluminum,  especially,  in  pig  iron. 
Hence  all  silica  residues,  for  strictest  accuracy,  should  be  evapo- 
rated with  an  excess  of  hydrofluoric  acid  and  two  or  three  drops 
of  sulphuric  acid,  then  ignited  and  weighed  again,  multiplying 
the  loss  of  weight  by  the  usual  factor,  and  dividing  by  the  weight 
taken  to  obtain  the  percentage  of  silicon. 

*  The  writer  uses  an  electrically  heated  muffle  ventilated  by  a  slow  stream  of 
compressed  air. 

f  For  close  work  it  is  always  advisable  to  use  the  hydrofluoric  acid  when 
chromium  is  present. 


CHAPTER  XII. 

PART  IX. 
THE  ANALYSIS  OF  CALCIUM  ELECTRO-SILICON. 

0.9  or  i.o  gram  of  the  floured  sample  is  fused  with  20  grams 
of  anhydrous  sodium  carbonate  ground  with  2  grams  of  niter 
in  a  platinum  crucible.  The  analysis  is  proceeded  with  as  in 
crucible  slag  (page  no),  obtaining  residues  A  and  B  which 
contain  all  of  the  silicic  acid  and  perhaps  a  small  portion  of  the 
calcium,  iron,  etc.  This  residue  is  weighed  and  hydrofluoric 
acid  is  added  to  it  very  slowly  at  first  and  finally  enough  of  this 
acid  to  fill  the  crucible  two-thirds  full.  Before  the  HF1,  ten 
drops  of  cone,  sulphuric  acid  are  added.  Then  evaporation  to 
fumes  follows  and  the  silicon  is  finished  as  in  steels.  Where 
such  large  amounts  of  silica  are  evaporated  it  is  well  to  add  more 
HF1  and  sulphuric  acid  and  repeat  the  volatilization  to  make 
sure  that  all  of  the  silica  has  been  removed.  The  stain  or 
residue  remaining  in  the  crucible  after  these  evaporations  is 
fused  with  a  gram  of  sodium  carbonate,  dissolved  out  with 
HC1  and  added  to  the  combined  filtrates  from  A  and  B  which 
will  now  contain  all  of  the  iron,  aluminum  manganese,  calcium 
and  magnesium.  A  double  basic  acetate  separation  of  the  iron 
as  given  on  pages  188  and  189  is  made.  The  acetate  precipitate 
from  the  second  precipitation  is  ignited,  dissolved  in  HC1,  pre- 
cipitated with  ammonia,  washed,  ignited,  and  weighed  as  oxides 
of  iron  and  aluminum.  These  oxides  are  then  dissolved  in  HC1 
and  the  solution  is  divided  into  two  equal  parts.  One-half  is 
reduced  with  stannous  chloride  and  finished  for  iron  as  in  iron 
ore.  The  other  half  is  converted  into  nitrate  and  finished  for 
phosphorus  as  in  steel.  The  iron  is  multiplied  by  two,  calculated 
to  ferric  oxide  and  deducted  from  the  total  oxides.  The  phos- 
phorus is  also  multiplied  by  two,  calculated  to  P20s  and  deducted 

287 


288 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


from  the  total  oxides.     The  remainder  after  these  deductions  is 
calculated  to  metallic  aluminum. 

The  nitrates  from  the  two  basic  acetate  precipitations  contain 
all  of  the  calcium  which  is  precipitated  with  ammonium  oxalate 
and  finished  in  the  usual  way  as  in  limestone.  The  manganese 
is  obtained  as  in  tungsten,  page  71. 

ANALYSIS. 


Silicon. 

Per  cent. 
eg  48 

Calcium 

Per  cent. 
30  86 

Iron 

7  08 

Carbon 

o  80 

Aluminum    .    .  . 

2   41 

Manganese. 

o  06 

The  carbon  is  gotten  by  ignition  of  0.5  gram  of  the  sample 
with  4  grams  of  red  lead,  or  litharge,  in  the  electric  furnace. 


CHAPTER  XIII. 

PART  I. 

THE    DETERMINATION    OF    URANIUM    IN    FERRO-URANIUM, 

CARNOTITE  ORE  AND  MIXTURES  OF  IRON,  VANADIUM, 

URANIUM  AND  ALUMINUM. 

THE  determination  of  uranium  in  ores  and  ferro-alloys  is 
usually  complicated  by  the  presence  of  vanadium  and  aluminum. 
The  writer  has  encountered  so-called  ferro-uranium  containing 
as  much  as  from  15  to  20  per  cent  of  aluminum  in  several  in- 
stances. Vanadium  w.as  always  present  from  2  or  3  per  cent 
to  as  high  as  28  per  cent. 

The  scheme  of  titrating  the  uranium  and  vanadium  together 
by  reducing  both  elements  in  sulphuric  acid  solution  with 
aluminum  was  tried  as  recommended  by  some  writers.  In  this 
method  the  total  amount  of  the  permanganate  standard  required 
to  reoxidize  both  elements  so  as  to  produce  a  slight  permanent 
pink  color  is  noted.  Then  the  vanadium,  alone,  is  reduced, 
this  time  to  V204  only,  by  adding  an  excess  of  sulphurous  acid 
(S02)  and  boiling  off  the  excess  of  the  latter.  The  vanadium 
is  then  oxidized  back  until  a  slight  permanent  pink  is  again 
obtained.  The  number  of  c.c.  of  the  KMnO4  required  in  this 
second  titration  is  multiplied  by  three  and  deducted  from  the 
amount  of  the  permanganate  used  in  the  first  titration.  The 
remainder  is  multiplied  by  the  uranium  value  of  the  perman- 
ganate, thus  obtaining  the  uranium.  In  the  writer's  hands  the 
results  were  discordant  whether  the  reduction  was  accomplished 
by  aluminum  or  zinc.  The  more  vanadium  present  the  worse 
disagreements,  and  the  less  vanadium,  the  more  nearly  the  true 
uranium  was  obtained.  With  uranium,  alone,  the  reduction 
with  permanganate  is  entirely  satisfactory. 

During  these  experiments  the  writer  tried  hydrogen  sulphide 


290  CHEMICAL   ANALYSIS   OF  SPECIAL   STEELS 

as  a  reducing  medium  and  found  that  H2S  reduces  both  vana- 
dium and  iron  but  does  not  reduce  the  uranium.  This  afforded  a 
way  of  determining  the  vanadium  in  the  presence  of  the  uranium 
but  has  no  advantage  over  the  method  of  the  writer,  to  be 
described.  The  H2S  reduction  makes  it  possible  to  determine 
both  iron  and  vanadium  in  the  presence  of  uranium,  in  fact  to 
determine  all  three  elements.  The  uranium  and  iron  together 
with  the  vanadium  carried  by  them  can  be  precipitated  by  a 
slight  excess  of  ammonia;  washed  with  ammonium  nitrate 
water;  ignited  at  a  low  red  heat;  moistened  with  cone,  nitric 
acid;  ignited  again  at  a  low  red;  cooled  and  weighed  as  Fe203, 
U3O8  and  some  V205  (aU  of  the  V2O5,  if  sufficient  of  the  Fe  and  U 
be  present).  The  weighed  oxides  are  dissolved  in  HC1;  evap- 
orated with  40  c.c.  of  i  13  H2S04  to  thick  fumes;  dissolved  in 
150  c.c.  of  water  and  the  vanadium  and  iron  in  the  mixture 
determined  as  given  on  page  29,  reducing  with  H2S.  The  Fe 
and  V  so  found  are  calculated  to  the  proper  oxides  and  deducted 
from  the  weight  of  the  total  oxides  above  mentioned  and  the 
uranium  oxide  is  thus  obtained  by  difference.  Similarly,  U 
and  Fe  alone  can  be  analyzed,  getting  the  iron  by  the  H2S  re- 
duction and  the  .uranium  by  difference.  Also  should  aluminum 
be  present,  the  total  oxides,  after  being  weighed,  can  be  dissolved, 
the  solution  be  divided  into  two  equal  parts  and  one  part  analyzed 
as  above  for  the  Fe2O3  and  V2O5,  and  the  other  part  analyzed 
for  aluminum  oxide  as  given  in  the  method  about  to  be  described. 
Deduct  twice  the  A12O3  +  Fe2O3  +  V2O5  found  from  the  weight 
of  the  total  A1203  +  U3O8  +  V205  +  Fe2O3,  obtaining  the  U3O8 
by  difference. 

The  author  devised,  tested,  and  is  now  -using  the  following 
method  for  the  determination  of  uranium  in  carnotite,  ferro- 
uranium  and  steel:  For  carnotite  ores  containing,  as  they 
usually  do,  from  i  to  4  per  cent  of  U3O8  weigh  2  grams  and 
3  grams  for  a  check.  For  ferro-uranium  do  not  take  over  i 
gram,  and  a  half  gram  for  a  check.  Dissolve  or  extract  the 
samples,  first  with  100  c.c.  of  cone,  nitric  acid  for  an  hour. 
Evaporate  to  dryness  in  the  casserole,  using  a  Royal  Berlin, 


URANIUM  IN  FERRO-URANIUM,   CARNOTITE  ORE,  ETC.      291 

porcelain  handled  casserole,  of  4!  inches  diameter.  Take  up  in 
100  c.c.  of  cone.  HC1,  evaporate  to  20  c.c.,  dilute  with  50  c.c.  of 
water  and  filter  out  the  insoluble  residue  consisting  mainly  of 
silica.  Wash  with  dilute  HC1  about  fifty  times.  Dilute  to 
300  c.c.;  nearly  neutralize  with  ammonia;  and  pass  H2S  in  hot 
solution  to  remove  any  Mo,  Pb,  Sn,  Cu,  As,  Bi  or  Sb  that  may  be 
present.  Filter;  wash  with  H2S  water,  thoroughly,  and  evap- 
orate the  filtrate  and  washings  to  20  c.c.;  add  an  excess  of 
chlorate  of  potassium,  about  i  gram  to  destroy  the  H2S,  also  50 
c.c.  of  HC1,  cone.,  and  heat,  covered,  until  all  spraying  is  over 
and  evaporate  to  20  c.c.  Transfer  to  a  liter  boiling  flask;  add 
sodium  peroxide  from  a  porcelain  spoon  to  the  300  c.c.  solution 
in  the  flask  until  a  slight  excess  is  obtained.  (It  should  be  said 
that  the  above  mentioned  insoluble  residue  is  evaporated  with 
an  excess  of  HF1  and  10  drops  of  cone.  H2SO4  and  the  remaining 
residue  is  fused  with  sodium  carbonate;  the  fusion  is  dissolved 
out  with  HC1  and  added  to  the  main  solution  in  the  liter  flask 
before  commencing  the  addition  of  the  sodium  peroxide.)  When 
an  excess  of  peroxide  has  been  added  to  the  solution  in  the 
liter  flask,  then  10  grams  of  ammonium  carbonate  are  added  to 
the  alkaline  solution;  next  in  order,  10  grams  of  sodium  car- 
bonate are  put  in,  and  last  of  all,  10  grams  excess  of  sodium 
peroxide  are  added.  The  solution  is  now  just  brought  to  in- 
cipient boiling,  and  immediately  removed  from  the  flame; 
cooled;  paper  pulp  is  added  and  the  solution  is  filtered  from  the 
iron  through  15  cm.  double  filters  into  800  c.c.  beakers.  The 
iron  on  the  filter  is  washed  with  a  mixture  consisting  of  5  grams 
each  of  sodium  and  ammonium  carbonates,  dissolved  in  500  c.c. 
of  water.  The  filtrate  and  washings,  which  should  have  a 
volume  of  not  less  than  400  c.c.,  are  now  neutralized  with  i  :  i 
HC1,  added  until  the  solution  no  longer  immediately  turns  a 
narrow  strip  of  turmeric  paper,  to  the  faintest  brown.  If  there 
be  alumina  present  to  the  extent  of  even  a  half  per  cent,  it  will 
have  clouded  the  solution  long  before  the  turmeric  ceases  to  be 
affected  by  the  solution.  Let  the  latter  stand  for  at  least  an 
hour  and  then  the  aluminum  can  be  filtered  out,  and  washed 


292  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

with  ammonium  nitrate  as  given  previously   (5   grams  of  the 
salt  to  500  c.c.  of  water). 

If  the  titration  with  acid  is  carefully  done  the  nitrate  and 
washings  will  not  contain  aluminum  even  though  there  be  in  the 
solution  the  equivalent  of  o.ioo  gram  of  Al.  The  filtrate  and 
washings  from  the  aluminum  will  contain  all  of  the  U  and 
much  of  the  V,  if  the  iron  present  does  not  exceed  more  than 
the  equivalent  of  o.ioo  gram  of  iron.  The  iron  can  be  dis- 
solved off  the  filter,  peroxidized  a  second  time  as  before  and  the 
alkaline  filtrate  and  washings  obtained,  keeping  them  separate 
from  the  filtrate  and  washings  gbtained  from  the  first  peroxida- 
tion.  These  two  nitrates  and  washings  are  then  made  entirely 
acid  after  the  removal  of  the  aluminum,  and  boiled  for  one  hour, 
or  until  all  CO%  is  removed  from  the  solution,  which  will  be 
accomplished  when  there  are  no  longer  any  more  lines,  or  fine 
threads  of  bubbles  coming  up  through  the  solution.  Then  the 
uranium  together  with  considerable  vanadium  is  precipitated  out 
with  a  slight  excess  of  ammonia.  The  solution  is  boiled  gently 
for  a  half  hour.  If  much  vanadium  is  present,  the  precipitate  will 
be  more  of  a  green  than  a  yellow;  but  if  much  uranium  and 
little  vanadium  be  present,  then  the  precipitate  will  take  on  a 
bright  yellow  color,  especially  after  heating  for  a  time.  The  pre- 
cipitate which  consists  mainly  of  uranium  vanadate  is  filtered  off 
and  washed  with  the  ammonium  nitrate  wash  (5  grams  to  500  c.c. 
of  water).  After  a  few  washings,  the  precipitate  is  dissolved  off 
the  filter  to  get  rid  of  any  occluded  salts,  reprecipitated,  and 
washed  as  before.  The  precipitate  is  now  ignited  in  a  platinum 
crucible,  or  a  porcelain  one  if  the  platinum  one  is  not  available, 
and  ignited  at  a  low  red  heat,  after  the  paper  has  been  smoked 
off.  The  ash  is  moistened  with  a  few  drops  of  cone,  nitric  acid, 
and  again  heated  to  a  low  red  heat;  cooled;  and  weighed  as  UsOg 
plus  ¥265.  The  weighed  oxides  are  dissolved  *  in  cone.  H^SCX; 
transferred  to  small  casseroles  and  evaporated  low  with  50  c.c.  of 

*  Do  not  use  HC1  at  this  point  as  chlorine  would  be  generated  and  the  plat- 
inum badly  attacked.  Use  10  c.c.  cone.  H2SO4  and  heat  for  an  hour,  or  until 
dissolved. 


URANIUM   IN  FERRO-URANIUM,   CARNOTITE  ORE,  ETC.     293 

HC1.  This  solution  is  then  evaporated  to  thick  fumes,  with  40 
c.c.  of  i  :  3  H2SO4;  cooled;  diluted  with  water;  filtered  from  the 
small  amount  of  silica  usually  present  which  is  washed  with 
dilute  sulphuric  acid;  ignited  and  weighed;  and  deducted  from 
the  UsOg  plus  ¥265.  The  nitrate  and  washings  from  this  silica 
contain  the  vanadium  that  was  precipitated  with  the  uranium. 
Owing  to  the  evaporation  with  the  large  excess  of  HC1,  the 
vanadium  is  now  reduced  to  V2O4.  It  can  be  titrated  to  a  per- 
manent pink  with  the  standard  permanganate  solution,  and  the 
vanadium  so  found  is  calculated  to  V2Oj>  and  subtracted  from 
the  silica  free  weight  of  the  above  oxides,  thus  giving  the  ura- 
nium by  difference.  Also  the  filtrate  and  washings  from  the 
small  amount  of  silica  can  be  heated  to  boiling  and  perman- 
ganate solution  added  cautiously  so  as  to  maintain  a  pink  solu- 
tion but  not  in  such  excess  as  to  produce  a  heavy  precipitate  of 
manganese  oxide  as  that  would  make  a  filtration  necessary.* 
The  boiling  is  continued  for  twenty  minutes.  If  the  solution 
still  remains  pink  with  perhaps  a  very  slight  precipitate  of  the 
manganese  oxide,  then  it  is  certain  that  all  organic  matter  that 
may  have  crept  in  during  the  analysis  is  rendered  harmless  as 
far  as  affecting  the  permanganate  standard  during  the  subsequent 
titration  is  concerned.  The  ferrous  ammonium  sulphate  standard 
is  now  added  to  the  hot  solution  until  the  pink  color  is  just 
removed  and  any  slight  5cloud  of  precipitated  manganese  oxide 
is  also  dissolved,  leaving  the  solution  perfectly  clear.  The 
solutions  of  the  tests  are  now  cooled,  and  an  excess  of  the  per- 
manganate standard  is  added  to  all  of  them.  Then  one  of 
them  is  titrated  drop  by  drop  with  the  sulphate  standard  until 
three  drops  at  room  temperature  give  but  a  faint  pink  that  re- 
mains practically  unchanged  for  one  minute.  This  is  the  start- 

*  Of  course  there  is  no  objection  to  boiling  with  an  excess  of  the  manganese 
oxide  except  the  extra  operation  involved.  Indeed  the  author  has  had  cases 
where,  owing  to  carbonaceous  matter  having  gotten  into  the  work,  probably  by 
extraction  from  filter  papers,  or  mechanically,  it  was  deemed  advisable  to  boil 
with  an  excess  of  permanganate  sufficient  to  produce  a  precipitate  that  remained 
even  after  a  half  hour  of  boiling.  This  brown  oxide  is  filtered  out  through  a  porous 
thimble  and  the  vanadium  titrated  exactly  as  described  on  page  35. 


294  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

ing  point  of  the  titration  with  the  ferrous  ammonium  sulphate 
standard.  The  volume  should  now  be  not  over  200  c.c.  Add 
2\  c.c.  of  the  ferricyanide  indicator  (5  grams  of  the  salt  dissolved 
in  130  c.c.  of  water)  and  then  the  ferrous  ammonium  sulphate 
standard  with  vigorous  stirring  until  three  drops  change  the 
dark  green  color  that  forms  to  a  distinct  blue,  i.e.,  to  the  first 
real  blue.  The  number  of  c.c.  of  the  sulphate  standard  required 
to  produce  this  blue,  after  the  addition  of  the  indicator,  mul- 
tiplied by  the  vanadium  value  of  the  sulphate  gives  the  vanadium 
that  was  carried  out  with  the  uranium.  It  is  calculated  to  VoOs 
and  the  uranium  is  thus  obtained  by  difference.  The  U308 
so  found  can  be  calculated  to  metallic  U  by  the  factor  0.8482. 
To  standardize  the  permanganate  and  sulphate  standards  for 
vanadium,  it  is  convenient  to  weigh  0.08  and  0.04  gram  of 
vanadium  pentoxide  of  known  purity  into  small  casseroles; 
dissolve  in  60  c.c.  of  cone.  HC1;  evaporate  low;  fume  with  40 
c.c.  of  i  :  3  H2SO4  and  carry  through  all  of  the  operations  lead- 
ing up  to  the  titration  with  KMnO4  and  the  final  titration  with 
the  sulphate.  This  will  give  the  blank  to  deduct  from  each 
method  of  titration  of  the  vanadium. 

For  checking  methods  and  manipulations  the  writer  used 
c.p.  uranium  nitrate  and  uranium  acetate  UO2(NO3)2  +  6H2O 
and  U02(C2H3O2)2  +  2  H2O,  respectively. 

A  mixture  that  approximates  to  the  general  run  of  carnotite 
ores  of  the  Colorado  mines  is  o.ioo  gram  of  uranium  nitrate, 
o.ioo  gram  of  the  Sibley  iron  ore  standard;  0.050  gram  of 
aluminum,  and  0.040  gram  of  V2O5.  (The  latter  can  be  ob- 
tained of  99.5  per  cent  V2O5.)  As  a  further  check,  the  author 
often  runs  a  mixture  of  double  the  above  amounts  of  uranium 
salt,  the  oxide  of  vanadium,  and  iron  ore.  These  mixtures  are 
put  through  all  of  the  operations  described. 

CALCULATIONS. 

For  the  benefit  of  those  who  wish  to  try  the  reduction  with 
aluminum  to  check  the  purity  of  uranium  nitrate,  or  who  may 
wish  to  assay  uranium  obtained  from  a  source  that  is  free  of 


URANIUM  IN  FERRO-URANIUM,  CARNOTITE  ORE,  ETC.      295 


296  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

vanadium,  the  method  in  general  is  to  convert  to  sulphates,  and 
heat  in  cone  flasks  in  the  presence  of  an  excess  of  from  20  to  30 
c.c.  of  cone.  H2SO4  diluted  to  100  c.c.  with  water.  A  coil  of 
1 8  gauge  aluminum  wire  of  T5g-  inch  diameter  and  about  7  inches 
long  *  is  placed  in  the  solution,  and  the  latter  is  heated  to  nearly 
boiling  for  2  hours  with  a  stream  of  purified  C02  passing  through 
a  perforated  watch  glass  into  the  cone  flask  to  prevent  the  en- 
trance of  air.  The  CO2  is  generated  by  the  action  of  HC1  (i  :  i) 
on  marble  and  passes  through  a  wash  bottle  containing  an  inch 
of  water  and  then  through  another  bottle  containing  a  similar 
depth  of  a  saturated  solution  of  sodium  carbonate.  After  the 
two  hours  reduction,  the  solution  is  cooled  with  CO2  passing, 
and  when  cold  the  aluminum  coil  is  removed  and  the  solution 
is  titrated  with  N/40  KMnO4  to  a  slight  permanent  pink.  A 
blank  is  also  run  at  the  same  time  and  deducted.  A  solution 
of  N/4O  should  equal  0.00298  gram  U  per  c.c.  The  equation  is 
2  KMnO4  +  5  UO2(SO3)2  +  2  H2O  =  2  KHSO4  +  2  MnS04  + 
5U03(S03)+H2S04. 

The  permanganate  is  standardized  with  sodium  oxalate 
(see  page  42). 

By  the  above  equation  we  see  that  2  gram  molecules  of  KMnO4 
equal  5  gram  atoms  of  U.  On  page  388  it  was  explained  that 
^  of  the  gram  molecule  of  permanganate  constitutes  its  normal 
solution  when  dissolved  in  a  liter  volume.  Hence,  2KMn04  =  5!!, 

or  KMnO4  =  — ,  so  that  4-  of  the  gram  molecular  weight  or  nor- 
2 

mal  KMn04  would  equal  |  the  gram  molecular  weight  of  uranium 
or  119.25  gram  of  U.  Therefore  i  c.c.  of  the  N/4O  KMn04  is 

equal  to  II9'     ,  or  0.00298  gram  of  U.     Having  found  by  titra- 
40,000 

tion  the  value  of  the  permanganate  standard  per  c.c.  in  sodium 
oxalate  as  given  on  page  42,  the  following  give  the  values  of  the 
N/4O  permanganate  in  U,  V  and  Fe. 

*  See  photo  No.  21. 


URANIUM  IN  FERRO-URANIUM,  CARNOTITE  ORE,  ETC.      297 
The  value  of  N/40  KMnO4  per  c.c.  in  gram  of  sodium  oxalate 
multiplied  by23  '^equals  its  value  in  gram  of  U  per  c.c. 


,         102.0  ,       .,  ,  r  TT 

by  -    —equals  its  value  in  gram  of  V  per  c.c. 
I34 

by  -  —  equals  its  value  in  gram  of  Fe  per  c.c. 
*34 

The  percentage  of  uranium  in  uranium  nitrate  is  47.45. 

The  percentage  of  uranium  in  uranium  acetate  is  56.17. 

The  percentage  of  uranium  in  uranoso-uranic  oxide  (UsOg)  is 
84.825. 

The  percentage  of  vanadium  in  vanadium  pentoxide  is  56.04. 

From  a  standardization  as  above,  the  author,  for  example, 
found  that  i  c.c.  of  N/4O  KMnO4  equals  0.00167  gram  of  sodium 
oxalate. 

i  c.c.  of  N/40  KMnO4  equals  0.00297  gram  of  uranium. 

i  c.c.  of  N/40  KMnO4  equals  0.001276  gram  of  vanadium. 

The  following  are  the  calculations  for  an  actual  analysis  of  a 
mixture:  o.ioo  gram  of  uranium  nitrate  crystals,  o.ioo  gram  of 
the  Sibley  iron  ore  standard,  0.05  gram  of  metallic  aluminum, 
and  0.040  gram  of  ¥265  of  99.5  per  cent  purity  were  put  through 
all  of  the  operations  in  the  method  as  described  and  the  following 
analytical  data  were  obtained: 

(1)  58.8  c.c.  of  sulphate  were  required  to  remove  all  pink 
and  brown  tints  from  60  c.c.  of  the  KMnO4  standard  (N/4o) 
placed  in  a  beaker  with  40  c.c.  of  i  :  3  sulphuric  acid  and  200  c.c. 
of  distilled  water.     As  i  c.c.  of  the  N/4O  KMnO4  was  found 
equal  to  0.001276  gram  of  V  then  i  c.c.  of  the  ferrous  ammonium 
sulphate  standard  is  equal  to  0.001276  X  60  divided  by  58.8  or 
0.0013  gram  of  V. 

(2)  The  U3O8  +  V2O5  obtained,  in  the  course  of  the  analysis, 
from  the  above  mixture  weighed  0.076  gram  after  deducting 
0.0014  gram  of  silica  found  in  it  on  dissolving  in  HC1. 

(3)  Beginning  at  the  point  where  the  U3O8  plus  V2O5  were 
dissolved  in  HC1;  evaporated  with  40  c.c.  of  1:3  H^SCX  to  thick 


298  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

fumes,  etc.,  0.020  and  0.040  gram  of  the  ¥265,  alone,  were  put 
through  all  of  the  subsequent  operations  and  the  vanadium 
therein  was  titrated  with  the  sulphate  standard  as  already 
described.  The  0.020  gram  required  10.1  c.c.  of  the  sulphate  to 
produce  the  blue  end  point,  and  the  0.040  consumed  18.8  c.c. 
(Blank  and  all).  The  0.020  gram  of  VzO$  contains  0.020X0.995 
X  0.5604  equals  0.01116  gram  V.  Now  we  saw  by  (i)  that  the 
sulphate  standard  has  a  value  of  i  c.c.  equals  0.0013  gram  of 
V,  hence  the  sulphate  required  to  unite  with  the  vanadium 
present  will  equal  0.001115  divided  by  0.0013  or  8.6  c.c.  This 
gives  10.1  c.c.  minus  8.6  c.c.  or  a  blank  of  1.5  c.c.  to  be  deducted 
from  all  tests. 

(4)  The  ¥265  in  (2)  was  determined  in  like  manner  and  found 
to  require  9.5  c.c.  of  the  sulphate.  We  have  just  seen  that  the 
calculated  blank  is  1.5  c.c.,  therefore  the  actual  V  in  (2)  required 
9.5  minus  1.5,  or  8  c.c.  Then  the  V^O*,  in  (2)  is  equal  to  0.0013  X 
8  divided  by  0.5604  or  0.0185  gram.  Hence  the  U308  in  (2)  equals 
0.076  minus  0.0185  or  °-°575  which  is  equivalent  to  0.0487 
gram  of  uranium.  The  uranium  contained  in  the  uranium 
nitrate  taken  equals  o.ioo  X  0.4745  or  0.04745  gram  of  uranium. 
This  gives  an  excess  of  0.0012  gram  of  U  found,  which  was  in 
all  probability  due  to  the  presence  of  a  little  Al  that  was  not 
removed  by  the  neutralization  with  the  i  :  i  HC1.  The  author 
would  recommend  that  the  operator  exercise  great  care  in  the 
neutralization.  The  acid  should  be  added  until,  as  already 
stated,  a  narrow  strip  of  turmeric  paper  dipped  into  solution  does 
not  show  any  more  change  than  a  similar  strip  dipped  in  water. 
It  is  also  advisable,  for  close  work,  to  allow  the  neutralized 
solution  to  stand  for  twelve  hours  before  filtering  out  the  alu- 
minum hydroxide. 

It  must  be  remembered  that  when  a  very  large  quantity  of  iron, 
for  instance  0.400  gram  of  iron,  is  to  be  separated  from  much  ura- 
nium, say  about  0.200  gram  of  U  and  o.ioo  gram  of  Al,  then  at 
least  three  peroxidations  will  be  required,  made  as  described  under 
carnotite,  to  remove  all  of  the  U  and  Al  away  from  the  iron. 
Then  when  the  Al  is  separated  from  the  U  by  the  acid  precipi- 


URANIUM  IN  FERRO-URANIUM,  CARNOTITE  ORE,  ETC.      299 


tation,  the  Al  is  almost  certain  to  carry  out  with  it  2  or  3  mgs. 
of  UsOg.  This  latter  can  be  removed  by  redissolving  the  Al  in 
the  hot  i  :  i  HC1;  the  solution  of  the  Al  is  treated  with  an  excess 
of  sodium  peroxide,  i.e.,  the  peroxide  is  added  to  it  in  a  liter  boil- 
ing flask  to  strong  alkaline  reaction;  then  add  5  grams  each  of 
sodium  carbonate,  and  ammonium  carbonate,  and  5  grams  sodium 
peroxide.  Bring  just  to  the  boil;  cool  and  precipitate,  as  already 
described,  to  the  turmeric  neutral  point  with  i  :  i  HC1 ;  let  stand 
for  12  hours  and  filter  out  the  Al  which  will  now  be  free  of  U. 
The  filtrate  from  the  Al  is  made  acid;  boiled  until  free  of  CO2; 
and  the  small  amount  of  U  is  precipitated  with  ammonia  in  slight 
excess,  boiling  gently  for  30  minutes.  The  U  is  filtered  out;  and 
added  to  the  main  portion  of  the  U  before  it  is  precipitated  with 
ammonia  the  first  time. 

Most  ferro-uranium  and  ferro-uranium-vanadium-aluminum 
alloys  will  dissolve  in  a  mixture  of  HC1  and  HNO3  but  the  author 
analyzed  one  such  alloy  that  contained  15  per  cent  of  silicon 
that  could  be  decomposed  only  by  fusing  it  twice  with  sodium 
peroxide.  The  following  results  attest  the  accuracy  of  the 
method: 


Uranium 

Uranium 

Uranium 

Uranium 

added. 

found. 

added. 

found. 

gram 

gram 

gram 

gram 

0.047 

0.048 

0.071 

0.0729 

0.047 

0.047 

0.047 

O  .  0468 

0.094 

o  .  0948 

0.094 

o  .  0950 

URANIUM  IN  STEEL  IN  THE  PRESENCE  OR  ABSENCE  OF  TUNG- 
STEN, CHROMIUM,  ALUMINUM,  COBALT,  NICKEL  AND  VA- 
NADIUM. 

Qualitative.  Dissolve  i  gram  of  the  steel  by  heating  it  with 
40  c.c.  of  i  :  3  sulphuric  acid.  When  action  is  over  add  15  c.c. 
of  i. 20  nitric  acid  and  heat  further  until  red  fumes  are  gone  and 
the  tungstic  acid,  if  present,  becomes  bright  yellow;  dilute 
with  100  c.c.  of  water;  warm  for  a  half  hour;  filter  out  the 
tungsten  and  wash  it  with  a  dilute  sulphuric  acid  water. 


300  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Dilute  the  filtrate  and  washings  from  the  tungsten  to  200  c.c. 
with  water  in  a  1000  c.c.  boiling  flask  and  per  oxidize  exactly  as 
described  in  the  gravimetric  method  for  carnotite.  Filter  out 
the  iron,  nickel,  cobalt  and  copper  and  wash  the  filter  a  few 
times  with  the  carbonate  water.  The  filtrate  and  washings  are 
then  rendered  just  neutral  to  turmeric  paper  with  i  :  3  sul- 
phuric acid.  Allow  the  neutral  solution  to  stand  for  several 
hours  before  filtering  out  any  silicic  acid  or  aluminum  hydroxide 
that  may  form  at  this  point.  Filter,  wash  with  ammonium 
nitrate  wash;  make  the  filtrate  and  washings  acid  with  H2S04; 
boil  the  filtrate  and  washings  gently  until  no  more  finely  divided 
bubbles  of  CO2  form.  Then  make  the  solution  slightly  ammo- 
niacal  and  heat  for  15  minutes.  Then  remove  from  the  flame 
when,  if  even  0.25  to  0.50  per  cent  uranium  be  present,  it  will 
give  a  considerable  yellow  precipitate  of  uranium  hydroxide 
which  will  contain  vanadium  if  the  latter  be  present.  If  much 
chromium  is  present  collect  this  precipitate  on  a  filter  to  note 
its  color,  which  should  be  yellow.  Any  aluminum  hydroxide  or 
silicic  acid  coming  from  the  reagents  and  appearing  at  this  stage 
when  filtered  off  and  washed  with  ammonium  nitrate  will  not 
show  yellow  but  will  be  white  on  the  filter.  The  operator 
should  add  enough  uranium  nitrate  crystals  to  i  gram  of  a 
chromium- tungsten  steel  to  equal  0.50  per  cent  of  U  and  put 
it  through  all  of  the  operations  along  with  the  steel  that  is  to  be 
tested  and  also  i  gram  of  the  known  steel  without  any  uranium 
added  and  he  can  then  compare  the  results  obtained  and  be 
able  to  form  a  very  sure  conclusion  as  to  the  presence  or  ab- 
sence of  U  in  the  unknown  steel. 

Quantitative.  The  gravimetric  method  is  carried  out  exactly 
as  the  qualitative  method  except  that  the  separations  with  the 
two  carbonates  and  the  peroxide  are  continued  until  there  is  no 
further  formation  of  a  yellow  precipitate  on  redissolving  the  iron 
precipitate  and  making  a  further  separation  of  the  uranium  as 
before.  Then  finish  the  determination  as  given  for  carnotite 
on  page  294,  beginning  at  the  point  where  the  uranium  vanadate 
is  filtered  off  and  washed  with  the  ammonium  nitrate  solution. 


CHAPTER  XIII. 

PART  II. 

THE  DETERMINATION  OF  VANADIUM  IN  SANDSTONES   CON- 
TAINING CARNOTITE,  ROSCOELITE,  AND  CALCIUM 
VANADATE,  ETC. 

(A)  IF  the  sandstone  contains  about  3  per  cent  V  then  take 
3  grams  of  the  finely  powdered  ore,  and  4  grams  for  a  check 
analysis.     Treat  the  ore  in  a  Royal  Berlin,  porcelain-handled 
casserole,  and  extract  it  with  100  c.c.  of  cone.  HNO3  for  a  half 
hour,  just  below  boiling,  with  frequent  stirring.     Then  remove 
the  cover  and  evaporate  to  dryness.     In  the  same  manner  extract 
this  residue  with  50  c.c.  of  cone.  HC1,  heating  with  the  cover  on 
until  all  red  fumes  are  gone.     Now  remove  the  cover,  and  evapo- 
rate low.     Add  50  c.c.  of  i  :  i  sulphuric  acid  and  evaporate  to 
heavy  white  fumes  to  remove  the  HC1.     Cool.     Add  50  c.c.  of 
water,  stir,  heat,  cool,  filter  off  the  insoluble  residue  and  wash  it 
with  dilute  sulphuric  acid  water.     Dilute  the  filtrate  and  wash- 
ings to  200  c.c.,  boil  with  permanganate  and  finish  the  deter- 
mination as  given  on  page  35. 

(B)  If  the  chemist  wishes  to  reassure  himself  that  even  the 
last  traces  of  vanadium  have  been  extracted  from  the  ore,  he  can 
burn  off  the  insoluble  residue  obtained  above  in  an  iron  crucible 
and  fuse  with  10  grams  of  peroxide  of  sodium.     The  fusion  is 
kept  hot  enough  to  keep  the  peroxide  just  molten  for  two  min- 
utes.    The  fusion  is  then  dissolved  out  in  the  manner  described 
on  page  140  under  Chromium  in  Chrome  Ore.     The  sulphuric 
acid  solution  is  filtered  from  any  iron,  scales  and  the  filtrate 
and  washings  are  then  analyzed  for  vanadium  as  above,  and  any 
vanadium  found  is  added  to  that  gotten  in  the  main  solution. 

It  is  well  for  the  operator  to  put  a  known  amount  of  vanadium 
through  all  of  the  operations  described  in  (A)  to  get  the  vana- 

301 


302  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

dium  value  of  the  standards  for  this  method.  Ferro-vanadium 
of  known  vanadium  content  is  decidedly  the  best  for  the  manip- 
ulation under  (A).  For  (B)  vanadic  acid  (¥265)  of  known 
purity  is  much  the  best  source  of  V. 

Almost  any  ore  of  vanadium  can  be  accurately  assayed  for 
vanadium  by  the  combination  of  (A)  and  (B).  The  sulphide 
ore  of  vanadium  (Patronite)  should  first  have  the  sulphur  roasted 
out  of  it  at  a  low  heat,  when  it  can  be  analyzed  according  to 
(A)  and  (B)  or  the  ash  can  be  fused  according  to  (B)  alone. 


CHAPTER  XIV. 

PART  I. 

QUALITATIVE  AND    QUANTITATIVE  TESTS  FOR  COBALT  AND 
NICKEL  IN  STEEL. 

DISSOLVE  0.500  gram  of  drillings  in  a  mixture  of  30  c.c.  1.20 
HC1  and  30  c.c.  of  cone,  nitric  acid.  Heat  until  the  insoluble 
residue  is  bright  yellow  if  tungsten  is  present.  Filter  on  a 
double  ii  cm.  filter;  wash  free  of  iron  with  i  :  10  HC1.  Make 
one  basic  acetate  separation  as  in  the  gravimetric  method;  filter, 
wash  a  few  times  with  acetate  wash.  Evaporate  the  filtrate 
washings,  if  necessary,  to  200  c.c.  Now  warm  the  solution  with 
a  drop  or  two  of  ammonia  to  see  if  any  small  amount  of  iron 
separates  out.  Filter  again,  as  iron  interferes  with  cobalt  test, 
and  wash  a  few  times  with  ammonia  wash;  add  an  excess  of 
dimethylglyoxime  to  the  ammoniacal  filtrate.  If  only  a  brown 
coloration  results  that  does  not  turn  to  a  scarlet  precipitate,  then 
cobalt  is  present.  If  a  scarlet  precipitate  forms  at  once  or  in 
a  few  minutes  then  nickel  is  present  (see  Brunck's  method  for 
nickel) . 

If  on  filtering  off  this  scarlet  precipitate,  after  one  hour's 
wait  the  filtrate  is  brown  in  color,  then  cobalt  is  also  present. 
0.25  per  cent  of  cobalt  in  0.500  gram  of  steel  gives  a  very  distinct 
brown  color.  The  writer  would  suggest  this  for  a  color  method 
for  small  amounts  of  cobalt.  If  only  a  slight  brown  coloration 
forms  on  adding  the  " dimethyl"  then  several  hours  should 
elapse  before  making  a  decision,  as  a  small  amount  of  nickel,  at 
first,  gives  only  a  brown  coloration  which  eventually  changes  to 
a  small  scarlet  precipitate. 

If  a  per  cent  or  two  of  cobalt  is  present  then  the  acetate  filtrates 
will  show  a  pink  coloration  which  is  in  itself  a  sure  proof  of  the 
presence  of  cobalt;  i.e.,  before  any  "dimethyl"  is  added.  This 
pink  color  looks  exactly  like  a  weak  solution  of  KMn04. 

303 


304  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

QUALITATIVE  TEST  FOR  COBALT  IN  STEEL  IN  THE  PRES- 
ENCE OF  NICKEL,  IRON,  CHROME,  ETC. 

Dissolve  i  gram  in  nitric  acid  or  in  the  before  mentioned 
mixture  of  nitric  and  hydrochloric  acid;  boil  down  to  20  c.c.; 
add  an  excess  of  ammonia.  Redissolve  in  glacial  acetic  acid; 
add  a  large  excess  of  potassium  nitrite  and  in  a  little  time  a  yel- 
low precipitate  of  potassium  cobaltic-cyanide  will  separate  out, 
and  look  very  much  like  the  yellow  precipitate  obtained  with 
molybdate  solution,  in  phosphorus  analysis. 

To  prevent  frothing  add  some  alcohol  immediately  after 
putting  in  the  potassium  nitrite. 

GRAVIMETRIC  METHOD  FOR  COBALT. 

In  steels  either  in  presence  or  absence  of  tungsten,  molybdenum, 
'vanadium  and  chromium. 

Weigh  i  gram  and  500  mgs.  of  sample  and  transfer  to  No.  5 
Royal  Berlin  porcelain  dishes.  Dissolve  each  in  a  mixture  of 
30  c.c.  cone.  HC1  and  30  c.c.  cone.  HNO3.  When  frothing  is 
over,  place  over  moderate  flames  on  graphite  baths  and  heat 
for  about  one  hour,  or  until  residue  in  dish  is  of  a  clean  bright 
yellow  color.  Rinse  ,off  cover  glasses  and  sides  of  dishes  with 
water,  then  add  100  c.c.  cone.  HNOs  and  take  to  dryness,  lower- 
ing flames  to  avoid  loss  from  spurting  when  contents  of  dishes 
are  nearly  dry.  (This  is  conveniently  accomplished  over  night.) 

Bake  over  a  bare  flame  until  nitric  fumes  are  driven  off.  When 
sufficiently  cool  to  prevent  cracking  the  dishes,  add  40  c.c.  cone. 
HC1,  and  with  cover  glass  on,  digest  for  30  minutes,  or  until  all 
soluble  constituents  are  in  solution;  boil  to  volumes  of  about  25 
c.c. ;  dilute  with  water  to  about  100  c.c. ;  and  evaporate  to  about 
75  c.c. 

Rinse  off  cover  glasses  into  dishes,  add  pulp,  filter  on  double 
ii  cm.  S.  &  S.  filters  into  600  c.c.  beakers.  Wash  precipitate, 
until  free  of  iron,  with  a  i  :  10  HC1  wash.  Set  aside  filtrate 
which  contains  the  bulk  of  the  cobalt. 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL    305 

TREATMENT  OF  THE  PRECIPITATE. 

Burn  off  in  clean  platinum  crucibles  to  yellow  powder,  using 
nickel  wire  to  break  up  hard  particles.  Weigh  when  cool,  add  2 
or  3  drops  HaSCX  and  10  c.c.  hydrofluoric  acid  and  drive  off  the 
SiF4  in  a  moderately  warm  muffle.  When  dry  remove  any  outside 
dirt  from  crucible  with  damp  cheese-cloth,  drive  off  SOs  fumes 
with  aid  of  a  Bunsen  or  Chaddock  burner  flame,  heating  finally 
to  redness;  cool,  weigh.  Loss  in  weight  represents  SiO2,  which, 
multiplied  by  0.4702,  gives  silicon.  Calculate  to  percentage. 

To  contents  of  each  crucible  add  8  grams  Na^COs.  Fuse  with 
lids  on  for  15  or  20  minutes.  Let  cool  slightly  and  extract  the 
melts  with  hot  water  in  platinum  dishes.  When  salts  are  in 
solution,  which  should  not  require  more  than  10  minutes  heating, 
remove  the  crucibles  and  rinse  them  thoroughly  with  water  into 
dishes  so  that  they  contain  no  carbonate.  Filter  on  double  No. 
9  cm.  S.  &  S.  filters.  Discard  this  filtrate.  Wash  precipitate 
with  water  until  free  of  alkali  to  phenolphthaleine.  Burn  off  in 
same  crucibles  in  which  fusions  were  made.  Weigh  when  cool. 

Difference  in  weight  between  the  final  silicon  free  weight  and 
this  one  represents  WO3,  which,  when  multiplied  by  0.7931,  gives 
tungsten.  To  the  final  residue  in  the  crucible  is  added  10  c.c. 
cone.  HC1  and  the  crucible  is  heated  gently  until  contents  are 
dissolved. 

Transfer  dissolved  content  of  each  crucible  to  its  respective 
beaker  which  contains  the  main  cobalt  filtrate.  Total  cobalt 
is  now  in  600  c.c.  beakers. 

Nearly  neutralize  with  ammonia.  Dilute  to  about  400  c.c. 
with  water.  Heat  to  80°  C.  and  pass  H^S  through  for  20  min- 
utes or  until  precipitate  separates  out  distinctly.  Remove  and 
let  settle  for  at  least  \  hour.  Filter  on  double  n  cm.  filters  into 
600  c.c.  beakers,  washing  precipitate  with  H2S  wash  (2  drops 
i  :  i  HC1,  500  c.c.  water,  sat.  with  H^S). 

Precipitate  contains  MoS3  and  other  metals  that  are  precipi- 
tated in  acid  solution.  Ignite  the  sulphides  at  a  low  red  heat 
in  porcelain;  extract  with  ammonia  and  filter;  wash  with  fil- 


306  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

tered  ammonia  water  and  again  weigh.  Loss  in  weight  is  MoOs, 
of  which  66f  per  cent  is  molybdenum. 

Filtrate  from  Sulphides.  Concentrate  to  about  50  c.c.,  add 
50  c.c.  cone.  HC1,  then  i  gram  KC1O3  and  concentrate  to  30  c.c., 
keeping  covered  until  all  fumes  of  chloric  acid  are  gone  to  pre- 
vent loss  by  spraying.  Dilute  to  150  c.c.,  add  50  c.c.  cone. 
HC1,  and  evaporate  to  50  c.c.  volume,  to  remove,  entirely,  the 
free  chlorine.  Finally,  dilute  to  300  c.c.  with  water,  add  am- 
monia until  a  faint  cloud  forms  that  will  not  stir  out.  Then 
add  20  c.c.  and  10  c.c.  of  ammonium  acetate  to  the  i  gram 
and  500  mg.  weights  respectively.  (2  c.c.  =  i  gram  ammonium 
acetate.*) 

Put  on  Argand  burner  stove  and  allow  them  to  boil  for  about 
2  minutes.  Remove  from  fire;  allow  acetates  to  settle;  filter 
through  double  15  cm.  filters  into  600  c.c.  beakers  that  have 
been  previously  boiled  out  with  dilute  HC1.  Wash  precipitate 
15  or  20  times  with  acetate  wash.  Set  aside  filtrates.  Dissolve 
precipitate  in  50  c.c.  HC1  (i  :  i)  by  heating  and  pouring  back 
and  forth  several  times,  then  washing  filter  free  of  iron  with 
i  :  10  HC1  wash.  Make  a  second  basic  acetate  separation, 
using  15  c.c.  and  8  c.c.  of  ammonium  acetate  respectively  for 
the  i  gram  and  500  mg.  weights.  Filter  into  600  c.c.  beakers 
and  wash  as  before. 

THE  COMBINED  ACETATE  FILTRATES. 

If  these  filtrates  contain  much  cobalt  they  will  be  pink.  Heat 
to  boiling;  make  faintly  ammoniacal;  add  5  c.c.  of  i  :  i  ammonia 
in  excess  and  last  of  all  50  c.c.  sat.  solution  of  microcosmic  salt. 
Stir  vigorously,  otherwise  bumping  may  break  beakers.  A  blue 
precipitate  forms  which  continuous  stirring  changes  to  a  crys- 
talline grape  colored  precipitate  that  settles  rapidly,  leaving  a 
water- white  supernatant  liquid.  Filter  on  n  cm.  filters  into 
clean  liter  beakers,  washing  precipitates  with  water  containing 
4  c.c.  ammonium  acetate,  until  free  of  chlorides,  testing  a  few 
drops  of  the  acidulated  washings  with  silver  nitrate  solution. 

*  Use  an  ammonium  acetate  solution  that  has  been  made  neutral,  or  very 
faintly  alkaline  with  ammonia. 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL     307 

Burn  off  precipitates  in  weighed  platinum  crucibles  over  low 
flame  at  first,  then  increase  to  bright  red  heat;  break  up  lumps 
with  a  nichrome  or  platinum  rod.  Cool,  and  weigh  as  cobalt, 
nickel  and  manganese  pyrophosphates  and  a  little  Si02  (C). 
Determine  manganese  in  a  separate  portion  by  sodium  arsenite 
titration,  calculate  to  Mn2P207  and  deduct.  Dissolve  contents 
of  crucibles  with  (i  :  i)  HC1;  filter;  wash  with  i  :  10  HC1,  then 
with  water;  burn  and  weigh  small  amount  of  silica  and  deduct 
from  (C).  The  remainder  is  CO2P2O7,  of  which  40.39  per  cent 
is  Co. 

The  filtrates  and  wrashings  from  the  phosphates  of  Co,  Ni 
and  Mn  usually  contain  a  little  Co  and  most  of  the  Ni,  etc., 
which  are  removed  by  saturation  with  EkS  in  hot  solution  as 
follows:  Heat  the  latter  to  70  or  80°  C.,  pass  EkS  through  for 
about  30  minutes.  Black  CoS  and  NiS  are  precipitated.  Filter 
on  double  n  cm.  filters  and  wash  about  50  times  or  until  free 
of  salts  with  water  containing  2  grams  ammonium  acetate  and 
saturated  with  H^S.  Burn  off  and  weigh  as  CoO,  of  which  78.66 
per  cent  is  Co.  Add  this  cobalt  to  that  found  from  phosphate 
precipitation  to  get  total  cobalt.  Deduct  the  Ni  found  on  a 
separate  portion. 

The  gravimetric  method  for  cobalt  powders  and  ferro-cobalt 
is  the  same  as  in  Co  steels  except  that  but  0.5  gram  is  taken 
for  the  Co  determination. 

VOLUMETRIC  METHOD  FOR  COBALT  IN  STEEL.     (PRE- 
LIMINARY REMARKS.) 

Cobalt  cannot  be  titrated  quantitatively  with  KCN,  exactly, 
as  nickel  owing  to  interfering  reactions  that  take  place.  If  the 
attempt  is  made  to  titrate  cobalt  alone  with  cyanide  and  silver 
a  black  precipitate  forms  that  obscures  the  end  point.  This 
is  due  to  the  formation  of  silver  cobaltic-oxide. 

The  writer,  after  several  months  of  experimenting,  found  that 
by  the  use  of  tartaric  acid  and  by  always  having  not  less  than 
i  gram  of  iron  in  solution  per  o.i  gram  of  Co  and  by  strict  ad- 
herence to  the  following  details,  titrations,  even  up  to  100  mgs. 


308  CHEMICAL  ANALYSIS  OF  SPECIAL   STEELS 

of  cobalt,  can  be  made  with  the  most  satisfying  accuracy:  Dis- 
solve 0.8  gram  and  i.o  gram  of  the  steel  in  40  c.c.  of  i  :  3  sul- 
phuric acid;  add  15  c.c.  of  1.20  nitric  acid  and  digest  the  steel, 
if  tungsten  be  present,  until  the  latter  is  bright  yellow;  cool;  add 
12  grams  of  tartaric  acid;  dilute  to  100  c.c.;  add  90  c.c.  of  i  :  i 
ammonia ;  drop  in  a  piece  of  litmus  paper  and  then  drop  in  i  :  3 
sulphuric  acid  from  a  burette  with  great  care,  until  the  litmus 
paper  just  turns  from  a  blue  to  a  red;  then  add  exactly  4  c.c.  of 
i  :  i  ammonia  in  excess  and  no  more,  before  titration  with  KCN". 

The  writer  uses  Kahlbaum's  c.  p.  cobalt  powder  for  standard- 
izations. Its  purity  can  be  checked  by  the  phosphate  method  as 
given  for  steels.  Nickel  in  cobalt  steels  and  metals  is  determined 
by  Brunck's  method. 

It  is  extremely  important  to  have  the  excess  of  ammonia  in  all 
tests  and  standardizations  mixtures  as  nearly  alike  as  possible. 
Varying  amounts  of  free  ammonia  cause  discordant  results,  ap- 
parently to  a  much  greater  degree  than  in  the  similar  titration 
for  nickel. 

VOLUMETRIC  DETERMINATION  OF  COBALT  IN  STEELS  CON- 
TAINING COBALT  WITH  OR  WITHOUT  TUNGSTEN, 
CHROMIUM,  VANADIUM  AND  MOLYBDENUM. 

Nickel  and  copper  interfere  and  must  be  removed  before  any 
attempt  is  made  to  titrate  the  Co,  or  determined  on  separate 
portions  and  deducted. 

Weigh  i  gram  and  800  mgs.  of  sample,  50  mgs.  and  40  mgs.  of 
c.p.  cobalt  along  with  i  gram  and  800  mgs.  of  cobalt,  nickel  and 
copper-free  steel  for  standards,  and  i  gram  of  the  same  non- 
cobalt  steel,  alone,,  for  a  blank  test,  into  600  c.c.  beakers  with 
cover  glasses.  Add  40  c.c.  H2SO4  (i  :  3)  to  each,  and  when 
most  of  action  is  over,  place  tests  on  Argand  burner  stove*  over 
low  flames  and  heat  until  all  soluble  material  is  dissolved; 
about  \  hour  is  required.  With  beakers  kept  covered,  intro- 
duce 15  c.c.  HNOa  (1.20)  through  the  lips  of  the  beakers; 
continue  heating  until  all  red  fumes  are  driven  off  (15  min- 

*  See  page  '258. 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL     309 

utes  required).  Remove  tests  from  stove,  rinse  cover  glasses 
and  sides  of  beakers  with  cold  water,  bringing  volume  of  each  to 
about  100  c.c.  Add  12  grams  of  powdered  tartaric  acid  to  each 
and  stir  until  dissolved.  Add  an  excess  of  ammonia  or  about  90 
c.c.  of  i  :  i  ammonia;  cool  and  proceed  with  the  neutralization  as 
described  under  "Preliminary  Remarks."  Place  beakers  in  pans 
containing  cold  water  so  as  to  bring  the  tests  down  to  room 
temperature. 

SOLUTIONS 


Cyanide  ....  9  grams  KCN     2000  c.c. 

2  grams  KOH     i  c.c.  =  about  0.00067  —  0.00069  gram  of  cobalt. 
Silver  Nitrate.  .  .  .  1.50  gram  AgNOs 

250  c.c.  H2O 
Potassium  Iodide  ....  50  grams  KI 

250  c.c.  H2O 

Add  exactly  4  c.c.  ammonia  (i  :  i)  to  each  neutral  test  solu- 
tion before  beginning  to  titrate.  It  is  very  important  that  the 
excess  of  ammonia  be  the  same  for  standards  and  tests.  (See 
preliminary  remarks.) 

Add  2  c.c.  KI  solution,  then  exactly  2  c.c.  AgNO3  solution, 
which  produce  quite  a  turbidity.  Stir  and  add  KCN  solution 
rapidly  at  first  and  slowly  toward  the  end  until  the  cloud  just 
disappears.  Record  time  at  that  moment  and  let  stand  6 
minutes.  Record  readings  of  "  Silver  "  and  "Cyanide  "  burettes. 

At  the  end  of  6  minutes  clear  up  the  newly  formed  cloud, 
slowly,  with  cyanide  and  add  the  amount  thus  used  to  that 
already  consumed.  Titration  is  now  finished.  Disregard  any 
subsequent  clouds  that  are  almost  certain  to  form.  Titration  of 
i  gram  of  a  non-cobalt  steel,  to  get  the  relation  between  cyanide 
and  silver,  is  the  next  step  and  is  as  follows:  After  dropping 
in  the  2  c.c.  of  KI  (from  small  pipette  or  graduate)  and  2  c.c. 
AgNOs  from  burette,  clear  up  carefully  and  slowly  with  KCN 
solution  rand  record  readings.  Since  all  steel  contains  at  least  a 
trace  of  copper  or  nickel,  this  titration  is  made  in  order  to  elimi- 
nate any  interference  from  this  cause.  This  having  been  done 
add  10  c.c.  KCN  solution,  then  carefully  bring  on  a  faint  cloud 


310  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

with  AgNOs  solution,  just  clearing  with  a  drop  or  two  of  KCN 
to  be  sure  of  no  appreciable  excess.  This  titration  gives  the 
relative  comparison  of  cyanide  and  silver  solutions,  showing  that 
i.i  c.c.  of  KCN  equal  i.o  c.c.  of  AgN03. 

The  calculations  are  the  same  as  in  the  similar  method  for 
nickel,  page  311.  Deduct  any  nickel  found  on  a  separate  portion 
by  Brunck's  method  or  the  modified  form  of  it.  It  is  quite 
unlikely  that  appreciable  amounts  of  nickel  will  be  found  in 
cobalt  steels.  The  same  can  be  said  of  copper,  although  the 
latter  can  be  removed  beforehand  by  H^S. 

STANDARDIZATIONS  AND  CALCULATIONS. 

Determine  the  blank  first.  Add  2  c.c.  KI  solution  then  2  c.c. 
AgNOs  solution.  Add  KCN  solution  drop  by  drop  until  white 
cloud  of  Agl  disappears.  Take  burette  readings  for  silver  and 
cyanide  solutions;  then  add  a  known  amount  of  cyanide,  about 
10  c.c.,  and  titrate  to  a  faint  cloud  with  silver  nitrate.  Calculate 
silver  nitrate  in  terms  of  cyanide,  e.g., 

ii. i  c.c.  KCN  =  10.1  c.c.  AgNO3. 

i  c.c.  AgN03  =  1.1  c.c.  KCN. 
Standard  mixtures: 

(1)  30  mgs.  Kahlbaum's  cobalt  and  800  mgs.  high  speed  steel. 

(2)  50  mgs.  Kahlbaum's  cobalt  and        i  gm.  high  speed  steel. 

(3)  80  mgs.  Kahlbaum's  cobalt  and        i  gm.  high  speed  steel. 

(4)  Blank,  no  cobalt  added  and  i  gm.  high  speed  steel. 

Put  the  above  mixtures  through  all  of  the  foregoing  operations 
until  the  point  of  titration;  then  add  2  c.c.  KI  solution,  also  ex- 
actly 2  c.c.  AgNO3 ;  then  with  constant  stirring  drop  in  KCN 
solution  until  the  cloud  disappears.  Record  first  and  last  read- 
ings of  burettes.  Note  the  time.  Wait  exactly  six  minutes, 
then  read  the  KCN  burette  and  clear  up  the  second  cloud 
cautiously.  Take  reading  and  add  it  to  former  KCN  reading. 
Deduct  (2.0  X  i.i)  c.c.  from  the  total  KCN  reading;  the  re- 
mainder represents  KCN  consumed  by  the  cobalt. 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL    311 


EXAMPLE. 

0.050  gm.  metallic  cobalt  used,  which  contains  97.21  per  cent  Co. 

KCN  to  clear  first  cloud.  KCN  to  clear  second  cloud.  AgNO3 

o.o                                                  71-2  I4-o 

69.9                                                  73-9  16.0 

69.9                                                    2.7  2.0 

2.7  Xi.i 

72.6  2.2 

—  2.2 

70.4  =  0.05    gm.  X  0.972   gm.    Co  =  0.0486    gm.    Co.,   or    i    c.c.    KCN 
=  0.0006904  gm.  cobalt. 

Titrate  sample  in  exactly  the  same  way  as  the  standard  mixtures.  Since 
800  mg.  weights  have  a  general  tendency  to  go  lower  than  i  gm.  weights  for  reason 
stated  in  the  introduction,  use  the  higher  factor  on  those  weights,  viz. : 

30  mg.  Std.  +  800  mg.  steel. 

i  c.c.  KCN  =  0.000704  gm.  cobalt. 


50  mg.  Std.  +  i  gm.  steel. 

i  c.c.  KCN  =  0.0006904  gm.  cobalt. 

800  mg.  sample  required  49.4  c.c.  KCN.  Therefore  the  steel  contained 
49.4  X  0.000704  mg.  Co  or  0.03477  mg.  Co.  Hence  per  cent  cobalt  in  sample 
equals  0.03477  -i-  0.8  X  100,  or  4.35  per  cent  cobalt. 

i  gm.  sample  required  63.0  c.c.  KCN.  Therefore  the  steel  contained  63.0  X 
0.0006904  gm.  Co,  or  0.04349  gm.  Co,  or  4.35  per  cent  cobalt. 

NICKEL  IN  COBALT  STEELS. 

Weigh  i  gm.  and  0.9  gm.  of  sample  into  400  c.c.  beakers.  Dis- 
solve in  25  c.c.  H2SO  (1:3)  over  moderate  flame.  Oxidize 
with  10  c.c.  HNOa  (i  :  20);  cool;  add  5  gms.  citric  acid  per  gram 
sample  taken.  Make  slightly  ammoniacal;  dilute  to  300  c.c.; 
add  20  c.c.  of  a  2  per  cent  alcoholic  solution  of  dimethylglyoxime ; 
let  stand  2  hours;  filter  on  double  n  cm.  filters;  wash  about 
25  times  with  dimethyl  wash  (10  c.c.  of  2  per  cent  dimethyl  to 
500  c.c.  water).  Dissolve  by  passing  25  c.c.  i  :  20  HNO3  (cold) 
back  and  forth  on  the  filter.  Wash  about  40  times  with  nitric 
wash  (10  c.c.  i  :  20  HN03  to  500  c.c.  water).  Make  filtrate 


312  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

ammoniacal  and  repeat  dimethyl  precipitation  to  remove  cobalt 
which  is  carried  out  with  nickel  in  considerable  quantity.  Filter 
and  wash  as  above.  The  precipitate  should  be  bulky  and  of  a 
brick  red  appearance.  If  not,  make  a  third  precipitation  to  in- 
sure complete  removal  of  cobalt.* 

Volume  of  dissolved  precipitate  should  be  about  100  c.c. 
Boil  about  10  minutes.  Add  15  c.c.  H2SO4  (i  13);  cool;  add 
2  gms.  citric  acid;  make  slightly  ammoniacal,  volume  about 
200  c.c.;  titrate  at  ordinary  room  temperature  in  usual  manner 
for  nickel  titration  in  plain  nickel  steel  by  the  KCN  method; 
calculate  per  cent  nickel  in  sample. 

When  nickel  is  present  along  with  cobalt  in  steels,  run  nickel 
standards  in  the  same  manner  as  described  for  cobalt  standards, 
i.e.,  clearing  up  of  first  cloud  after  waiting  6  minutes.  Per  cent 
nickel  having  been  determined  by  separate  operation,  calculate 
number  of  c.c.  used  for  nickel  by  dividing  amount  of  nickel 
found  by  the  nickel  value  of  the  cyanide  solution  standardized 
as  above;  deduct  from  total  KCN  used  by  the  cobalt  plus 
nickel  and  calculate  cobalt  by  multiplying  the  remaining  c.c. 
by  the  cobalt  value  of  the  solution. 

STANDARDIZATION  OF  KCN  SOLUTION,  WITH  NICKEL  AMMONIUM 
SULPHATE,  FOR  COBALT  NICKEL  STEELS. 

200  mgs.  Ni.  Am.  Sulphate.  800  mgs.  High  Speed  Steel. 

KCN  to  clear  first  cloud.                        KCN  to  clear  second  cloud.  AgNOj 

19.3  58.0                                                 48.0 

51.6  58.4                                                50-0 

32.3  0.4                                                   2.0 

-.4  Xl.i 

32-7  2.2 
2.2 

3oT 

0.0146  gm.  of  Ni  in  o.ioo  gram  of  Ni.  Am.  sulphate 

0.0146  gm.  X  2  -T-  30.5  =  0.000957  or 

i.  c.c.  KCN  solution  equals  0.000957  gm.  nickel. 

*  A  nitrate  at  this  point,  free  from  brown  color,  indicates  the  complete  removal 
of  the  cobalt  from  the  red  nickel  precipitate. 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL    313 

340  mgs.    Ni.  Am.  Sulphate.  i  gm.  High  Speed  Steel. 

KCN  KCN                             AgN03 

1.2  78.6                             52-° 

54-Q  80.6                           54-Q 

52.8  2.0                                       2.0 
+  2.0 

54-8 

2.2 


52.6 

0.0146  X  3.4  -*•  52.6  equals  0.0009437  or 

i  c.c.  KCN  solution  equals  0.0009437  gm.  nickel. 

CALCULATIONS  FOR  COBALT  IN  COBALT  NICKEL  STEELS. 

Sample  800  mgs. 

ist  titration.  2nd  titration. 

AgNO3  KCN  KCN  required  to  clear  second  cloud 

which  formed  after  six  minutes. 

54.0  0.2  i.o 

56.0  78.4  5-7 

2.0  78.2  4-7 

4-7 
82.9 

2.2 

8oT7 

27.6 


Cobalt  and  nickel  required  80.7  c.c.  KCN  in  0.8  gram  of  sample.  Since  3.26  % 
nickel  was  found  by  separate  determination,  therefore  0.0326  X  0.8  =  0.02608  gram 
nickel,  which  divided  by  0.00095  =  27.45,  or  27.45  c.c.  of  KCN  to  be  deducted  from 
the  total,  or  80.7  c.c.  This  gives  80.7  —  27.45,  or  53.25  c.c.  of  KCN  used  by  cobalt 
alone.  53.25  X  0.00068  X  100  •£•  0.8  =  4.52  per  cent  Co. 

Sample  i  gm. 

ist  titration.  2nd  titration. 

AgNO3  KCN  KCN  required  to  clear  the  second  cloud 

which  forms  after  six  minutes. 

56.0  0.6  57.0 

58.0  99  .o  62.2 

2.0  98.4  5.2 

5-2 
103.4 

2.2 


IOI.2 
34-3 
66.9 


Cobalt  and  nickel  required  101.2  c.c.  of  KCN  for  i  gm.  sample.  Since  3.26 
per  cent  nickel  was  found  by  separate  determination,  therefore  0.0326  X  i.o-f- 
0.00095  =  34-31-  I01-2  ~  34«3  =  66.9  or  KCN  used  by  cobalt  alone.  66.9  X 
0.00068  -T-  i  X  ioo  =  4.55  per  cent  cobalt. 


314  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

THE  DETERMINATION  OF  SMALL  AMOUNTS  OF  NICKEL  IN 
THE  PRESENCE  OF  LARGE  PER  CENTS  OF  COBALT. 

Dissolve  i  or  more  grams  of  the  cobalt  in  40  c.c.  of  1.20  nitric 
acid;  add  15  c.c.  of  i  :  3  H2S04;  boil  off  nitrous  fumes;  cool; 
add  5  grams  of  citric  acid  per  gram  of  cobalt  taken;  add  a  slight 
excess  of  ammonia.  Cool  and  add  20  c.c.  of  a  2  per  cent  solution 
of  the  dimethylglyoxime  in  95  per  cent  alcohol  for  every  gram 
of  metallic  cobalt  present.  Let  the  cold  solution  stand  for  at 
least  one  hour;  filter  out  the  precipitate  of  the  nickel  com- 
pound which  owing  to  contamination  with  Co  may  not  have  its 
true  scarlet  color.  It  is  washed  with  "dimethyl"  wash  con- 
sisting of  10  c.c.  of  the  dimethyl  solution  diluted  with  500  c.c.  of 
water,  and  is  redissolved  in  25  c.c.  of  1.20  nitric  acid,  and  re- 
precipitated  as  before.  The  now  scarlet  precipitate  is  washed 
as  at  first;  dissolved;  15  c.c.  of  i  :  3  sulphuric  acid  are  added  to 
the  solution  which  is  then  boiled  15  minutes.  5  grams  of  citric 
acid  are  added  and  the  nickel  is  titrated  with  cyanide  and 
" silver"  as  in  steels.  This  method  should  answer  for  the  sepa- 
ration of  small  amounts  of  nickel  from  large  amounts  of  elements, 
like  manganese  and  chromium,  which  give  very  dark  fluids  when 
held  in  ammoniacal  solution  by  ammonium  citrate.  In  this  way 
large  weights  of  these  elements  could  be  taken  as  in  the  case  of 
the  Co. 

THE  TESTING  OF  NICKEL  FOR  SMALL  AMOUNTS  OF  COBALT. 

Dissolve  4  or  5  grams  of  the  nickel  millings  in  1.20  nitric  acid, 
using  10  c.c.  of  the  acid  for  every  gram  of  the  sample  taken. 
Boil  off  the  red  fumes;  dilute  to  20  c.c.;  add  ammonia  until  a 
slight  precipitate  forms  that  does  not  dissolve  on  long  stirring,  if 
iron  or  aluminum  be  present;  if  neither  of  these  elements  are  in 
the  solution  then  add  the  ammonia  until  a  piece  of  litmus  paper 
floating  in  the  solution  just  turns  blue.  Now  add  acetic  acid 
(i  part  of  glacial  acetic  acid  diluted  with  an  equal  volume  of  water) 
until  the  precipitate  just  dissolves,  or  the  litmus  turns  to  red, 
or  the  solution  smells  of  a  slight  excess  of  acetic  acid;  add  an 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL     315 

excess  of  10  c.c.  of  the  acetic  acid;  dilute  the  solution  to  400  c.c. 
and  add  25  grams  of  potassium  nitrite  when,  after  a  few  minutes, 
the  solution  will  begin  to  cloud  with  a  precipitate  of  the  tri- 
potassium  cobaltic  nitrite.  If  the  percentage  of  Co  present  is 
very  small,  being  less  than  o.i  per  cent,  then  the  precipitate  will 
appear  yellow  only  after  the  lapse  of  an  hour  or  two.  If  there  be 
from  0.3  to  0.5  per  cent  of  Co  in  the  sample  then  the  cobalt  will 
quickly  form  in  a  bright  yellow  powder,  and  slowly  settle  to  the 
bottom  of  the  beaker.  After  standing  12  hours  the  precipitate 
is  filtered  off  and  washed  with  25  grams  of  potassium  nitrite 
dissolved  in  300  c.c.  of  water  and  made  slightly  acid  with  acetic 
acid.  The  precipitate  should  be  mixed  with  some  finely  divided 
filter  pulp  before  filtering.  Wash  it  until  the  washings  no  longer 
give  any  color  with  a  solution  of  dime  thy  Iglyoxime. 

The  yellow  precipitate  is  then  dissolved  in  40  c.c.  of  hot  i  :  i 
HNOs  and  the  filter  is  thoroughly  washed  with  the  acid.  The 
filtrate  and  washings  are  made  slightly  ammoniacal  and  20  c.c. 
of  "dimethyl"  are  added  to  each  test.  This  gives  a  brown 
color  whose  depth  is  proportional  to  the  cobalt  present  and  is 
compared  with  known  amounts  of  cobalt  ammonium  sulphate 
put  through  all  of  the  above  operations.  The  color  is  almost 
exactly  the  same  shade  as  that  obtained  in  the  color  carbon 
test  in  steels. 

If,  when  the  yellow  cobalt  precipitate  is  washed  with  the 
above  nitrite  wash,  it  is  found  that  the  nickel  is  very  difficult  to 
remove,  the  yellow  precipitate  can  be  redissolved,  reprecipitated 
and  washed  again.  This  treatment  should  remove  the  nickel  to 
the  extent  that  the  cobaltic-nitrite  can  be  readily  washed  free 
of  nickel  test  with  the  "  dimethyl  "  wash. 

The  above  procedure  constitutes  a  very  delicate  qualitative 
test  for  cobalt  in  the  presence  of  nickel.  Less  than  o.ioo  per  cent 
of  Co  can  be  readily  detected  in  5  grams  of  nickel.  The  oper- 
at  or  should  be  careful  to  carry  out  either  the  qualitative  or  the 
quantitative  precipitation  exactly  as  described  for  the  quanti- 
tative method,  as  there  are  conditions  which  cause  the  cobalt 
to  precipitate  very  slowly  and  imperfectly.  If,  when  the  nitric 


316  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

acid  solution  of  the  yellow  precipitate  is  made  ammoniacal, 
prior  to  the  addition  of  the  " dimethyl"  to  obtain  the  brown 
color,  a  precipitate  of  iron  appears,  this  iron  must  be  removed  as 
iron  also  gives  a  color  with  this  reagent.  Make  a  basic  acetate 
separation  of  the  iron,  in  the  usual  way,  in  a  volume  of  100  c.c. 
Make  a  second  basic  acetate  separation  of  the  iron  and  combine 
the  two  nitrates  and  washings  from  the  basic  acetate  precipi- 
tations; make  ammoniacal;  add  the  " dimethyl"  and  compare 
with  the  standard  similarly  treated,  consisting  of  0.2  gram  of 
cobalt  ammonium  sulphate  put  through  all  of  the  above  opera- 
tions. 

ANALYSIS  FOUND. 


Cobalt 

Per  cent. 
O  600 

Silicon 

Per  cent. 
O   28 

Nickel     . 

98  400 

Manganese 

trace 

Iron  

O.6o 

Copper  

O.I2 

ELECTROLYTIC  METHOD  FOR  COBALT  AND  NICKEL  IN  FERRO- 
COBALT  AND  IN  COBALT  POWDER. 

The  following  method  is  used  by  one  large  German  concern  for 
the  valuation  of  their  product:  20  grams  are  dissolved  in  mod- 
erately cone,  nitric  acid.  Any  insoluble  matter  is  fused  with 
KHSO4  and  the  fusion  is  dissolved  in  diluted  H2SO4  (i  13), 
added  to  the  main  solution  and  then  all  is  transferred  to  a  liter 
volumetric  flask,  diluted  to  mark  and  mixed  well  by  repeatedly 
inverting  the  flask.  25  c.c.  of  this  solution  are  accurately 
measured  from  a  50  c.c.  burette  that  has  been  rinsed  three 
times  with  some  of  the  liter  solution.  These  25  c.c.  are  evapo- 
rated to  thick  fumes  with  H2SO4;  diluted  to  350  c.c.  with  water; 
and  the  copper  is  precipitated  with  H2S.  The  Cu2S  is  filtered 
out  and  washed  with  H2S  water  containing  a  drop  of  H2S04  in 
500  c.c.  The  nitrate  and  washings  from  the  Cu2S  are  evaporated 
low,  in  a  casserole;  5  c.c.  cone.  HNOs  are  added  and  75  c.c. 
of  cone.  HC1;  heated  with  lid  on  until  all  red  fumes  are  gone; 
the  lid  is  removed  and  evaporation  to  10  c.c.  follows.  Dilute  to 
350  c.c.;  make  a  double  basic  acetate  separation  of  the  iron  as  in 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL    317 

gravimetric  method;  add  2  c.c.  of  acetate  per  100  mgs.  of  cobalt 
present;  filter  off  any  iron  acetate,  wash  with  acetate  water.  To 
filtrate  and  washings  add  35  c.c.  H2SO4  of  30  degrees  Be  and  evapo- 
rate to  fumes;  take  up  with  water  and  add  2  grams  of  sodium 
sulphite,  also  about  40  c.c.  of  ammonia  of  about  0.96  sp.  gr.  The 
strongly  ammoniacal  solution  should  now  be  about  100  c.c.  vol- 
ume. Electrolyze  this  solution  in  the  cold  with  a  current  of  0.3 
to  0.4  amp.  and  6  volts  for  about  6  hours,  using  a  platinum  spiral 
and  a  gauze  electrode  of  platinum.  Weigh  as  cobalt  plus  nickel. 

DETERMINATION  OF  THE  NICKEL. 

100  c.c.  of  the  liter  solution  are  neutralized  with  KOH  and 
KCN  is  added  until  the  precipitate  that  forms  is  dissolved.  Add 
an  excess  of  KOH;  add  bromine  water  until  a  yellow  color  is 
obtained;  and  allow  the  precipitate  to  settle  for  i  hour.  The 
black  precipitate  of  nickel  oxide  which  still  contains  a  little 
cobalt  is  filtered,  washed  with  KOH  water  and  redissolved  in 
HC1  containing  bromine  water.  This  Ni  is  then  reprecipitated 
as  before,  redissolved  and  the  solution  is  electrolyzed  for  nickel 
as  in  the  case  of  the  Co.  The  nickel  is  then  dissolved  off  the 
electrode  with  HNOs.  The  nitric  solution  can  be  titrated  with 
KCN. 

The  German  method  precipitates  the  solution  of  the  deposited 
nickel  with  a  i  per  cent  alcoholic  solution  of  dimethylglyoxime  at 
50°  C.  in  excess  of  ammonia.  Dry  the  precipitate  to  constant 
weight  at  120  degrees.  The  nickel  is  then  deducted  from  the 
cobalt  plus  nickel  determined  from  the  25  c.c.  by  electrolysis, 
and  the  cobalt  obtained  by  difference. 

THE  METHOD  GIVEN  IN  DETAIL  FOR  THE  DETERMINATION 

OF  COBALT  AND  NICKEL  BY  ELECTROLYSIS  AS 

USED  BY  THE  AUTHOR. 

For  cobalt  powder,  cube  or  ferro-cobalt  containing  70  per  cent 
or  more  of  Co,  dissolve  0.2  gram  (and  0.3  gram  for  a  check)  in 
35  c.c.  of  i  :  3  sulphuric  acid,  using  600  c.c.  beakers.  When  the 


318  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

action  is  over,  oxidize  any  iron  by  the  addition  of  10  c.c.  of  1.20 
nitric  acid;  boil  down  to  15  c.c.;  add  50  c.c.  of  water  and  boil 
again  to  15  c.c.;  cool;  make  the  basic  acetate  separation  of  the 
iron  in  the  same  way  as  described  under  ferro-manganese,  page 
1 88.  Add  2  c.c.  of  the  slightly  ammoniacal  ammonium  acetate 
solution  for  each  100  mgs.  of  cobalt  present.  Filter  out  the  acetate 
of  iron;  redissolve  it  and  repeat  the  basic  acetate  separation. 
The  combined  nitrates  from  the  two  basic  acetate  separations 
are  acidulated  with  10  c.c.  of  H2S04  and  evaporated  to  200  c.c. 
Ammonia  is  added  until  the  solution  takes  on  the  faintest  excess 
of  ammonia.  Then  100  c.c.  more  of  i  :  i  ammonia  are  dropped 
in  and  2  grams  of  sodium  sulphite.  The  solutions  are  .trans- 
ferred to  400  c.c.  beakers  and  electrolyzed  with  a  current  of  0.45 
ampere  and  3.2  volts  until  the  pinkish  solution  is  entirely  color- 
less. The  electrolysis  is  conducted  in  pairs.  The  current  is 
turned  on  and  allowed  to  run  all  night. 

The  beakers  are  arranged  so  that  they  can  be  lowered  away 
from  the  electrodes  when  the  deposition  of  the  cobalt  is  com- 
pleted. The  electrodes  are  rinsed  off  with  distilled  water;  and 
another  beaker  is  slipped  under  them  and  raised  and  lowered 
with  the  electrodes  dipping  in  the  water;  a  second  and  third 
beaker  of  water  are  also  used  to  wash  the  electrodes  as  many 
more  times.  The  cathode  is  then  dried  in  an  air  bath  at  100°  C. 
for  45  minutes;  cooled;  and  weighed.  It  is  again  washed; 
dried  cooled;  and  weighed.  The  final  weight  less  the  weight 
of  the  cathode,  taken  before  the  analysis,  equals  the  weight 
of  the  cobalt,  and  any  nickel  present.  The  author  has  found 
nickel  from  traces  to  3%,  in  every  case  thus  far,  of  cobalt  of 
commerce. 

The  sketch  No.  22  shows  an  arrangement  of  electric  lamps 
whereby  the  amperage  can  be  varied  from  0.225  to  0.9  ampere, 
and  from  which,  with  a  .220  volt  circuit,  an  electromotive  force 
of  3.2  volts  can  be  obtained.  At  the  points  marked  16  c.p.,  16 
candle  power  lamps  are  placed  in  the  circuit.  A  32  candle  power 
lamp  is  put  in  the  socket  so  marked.  With  one  16  c.p.  lamp 
burning  the  current  is  0.225  ampere;  with  two  such  in  action 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL     319 

the  amperage  is  0.45  and  so  on.  With  the  32  lamp  the  current 
is  0.45.  With  all  three  lamps  the  amperage  is  the  sum  total, 
or  0.9.  The  voltage  on  the  main  is  220.  This  group  of  lights 
can  be  arranged  on  a  board  8  by  10  inches.  One  such  group  is 
of  course  needed  for  each  determination.  To  determine  which  is 
anode  and  which  is  cathode,  close  the  switch,  wet  a  piece  of  tur- 


Cathode 


Anode 

SKETCH  No.  22. 


meric  paper  and  touch  the  ends  marked  "anode  "  and  "cathode" 
to  the  paper,  when  the  end  which  is  cathode,  or  negative,  will 
stain  the  turmeric  red. 

,  The  solution  from  which  the  Co  and  Ni  have  been  deposited, 
is  saturated  with  H2S,  and  any  small  amount  of  black  suphide 
that  separates  out  is  filtered  out;  washed  with  H^S  water; 
ignited  in  a  porcelain  crucible  at  a  low  red  heat;  weighed  as  CoO; 
multiplied  by  the  factor  0.7866  to  convert  it  to  the  equivalent 


320  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

of  metallic  Co;  and  added  to  the  total  of  Co  plus  nickel  found 
on  the  cathode.  The  cathode  is  then  placed  in  hydrochloric 
acid,  which  quickly  dissolves  off  the  Co  and  Ni.  The  cathode  is 
removed  and  rinsed  thoroughly.  To  the  solution  and  rinsings  are 
added  the  solution  of  the  small  amount  of  the  oxide  which  has 
meanwhile  been  dissolved  in  a  little  aqua  regia.  Make  the 
total  solution  ammoniacal  and  precipitate  the  nickel  out  of  the 
hot  solution  with  20  c.c.  of  the  2  per  cent  solution  of  dimethyl- 
glyoxime  in  alcohol.  The  red  precipitate  is  dissolved  in  nitric 
acid;  reprecipitated  as  before;  washed  with  dilute  nitric  acid 
water;  and  finished  by  the  ordinary  titration  with  KCN  and 
silver  nitrate.  The  milligrams  of  metallic  nickel  so  found  are 
deducted  from  the  total  of  Co  and  Ni  found  by  the  electrolysis 
plus  any  recovered  by  H2S,  giving  the  cobalt  by  difference.  If 
the  operator  wishes  to  guard  against  the  presence  of  copper,  H^S 
should  be  passed  through  the  solution  of  the  total  cobalt  plus 
nickel  before  adding  the  dimethyl.  Any  sulphides  so  pre- 
cipitated are  filtered  out;  washed  and  titrated  with  KCN  for 
copper  as  in  steels.  The  filtrate  and  washings  from  the  copper 
are  evaporated  low;  oxidized  with  nitric  acid;  and  then  the 
nickel  is  obtained  with  the  dimethyl,  as  described.  If  the 
operator  wishes,  the  nickel  can  be  gotten  on  a  separate  por- 
tion as  described  under  the  determination  of  nickel  in  metallic 
cobalt. 

The  cylindrical  cathode  and  disc  anode  of  platinum  are  the 
most  convenient  form  of  electrodes  for  this  work.  One  can  use 
also  a  platinum  dish  for  the  cathode,  suspending  in  the  fluid  in 
the  dish  any  convenient  form  of  platinum  anode. 

Phosphorus,  sulphur  and  silicon  can  be  determined  in  metallic 
cobalt  as  in  plain  carbon  steel.  In  all  of  the  samples  that  the 
author  has  analyzed,  at  least,  very  accurate  results  for  sulphur 
were  obtained  by  the  ordinary  evolution  method.  These  results 
were  checked  by  gravimetric  results  obtained  by  the  same 
method  as  recommended  for  sulphur  in  tungsten  powder  by 
fusing  with  a  mixture  of  sodium  carbonate  and  sodium  peroxide. 
See  page  73. 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL     321 


MANGANESE  IN  HIGH  PERCENTAGE  COBALT  STEEL  AND 
METALLIC  COBALT. 

Dissolve  o.ioo  and  0.05  gram  of  steel,  cobalt  powder,  or  ferro- 
cobalt  in  20  c.c.  of  cone.  HC1  diluted  with  10  c.c.  water.  Dilute 
to  50  c.c.  and  neutralize  with  ammonia.  Redissolve  the  hydrox- 
ides in  glacial  acetic  acid.  Avoid  much  excess  of  acetic  acid. 
Dilute  to  100  c.c.  with  water  and  pass  H2S  in  the  cold  to  remove 
the  main  portion  of  the  cobalt.  Filter  off  cobalt  sulphide,  wash 
it  50  times  with  H2S  water,  evaporate  filtrate  and  washings  in  a 
casserole  to  20  c.c.;  cool;  add  100  c.c.  cone,  nitric  acid;  heat  with 
cover  on  until  all  red  fumes  are  gone;  remove  cover  and  evap- 
orate to  25  etc.  Dilute  to  50  c.c.  with  water  and  evaporate 
again  to  25  c.c.  Transfer  to  10  by  i  inch  test  tubes  and  finish 
as  in  plain  carbon  steel.  The  bulk  of  the  cobalt  is  removed  only 
because  it  gives  such  a  strong  pink  in  nitric  solution  that  the 
operator  cannot  get  an  end  point  when  titrating  with  arsenious 
acid  as  in  steels.  Steels  containing  5  per  cent  Co  do  not  inter- 
fere in  this  way,  but  if  the  percentage  of  Co  runs  much  higher, 
the  cobalt  must  be  removed  before  titration. 

Cobalt  steels  containing  much  chromium  and  tungsten  should 
be  dissolved  in  20  c.c.  of  i  :  3  H2SO4  and  oxidized  with  15  c.c. 
i  :  20  nitric  acid;  boil  down  to  10  c.c.;  filter  off  tungsten;  wash 
with  dilute  H2S04;  neutralize  with  ammonia;  acidulate  with 
acetic  acid  and  proceed  as  above.  This  removal  of  cobalt  is 
only  necessary  in  very  high  percentages,  at  least  10  per  cent 
cobalt. 

ANALYSES  OF  METALLIC  COBALT  AND  FERRO-COBALT. 


Per 
cent 
Co 

Per 
cent 
Ni 

Per 
cent 
Fe 

Per 
cent 
Al 

Per 
cent 

Si 

Per 
cent 
S 

Per 
cent 
Mn 

Per 
cent 
P 

Bar  cobalt  
Lump  cobalt  

94.40 
98.56 

2-59 
0.8o 

0.48 

I.I7 

0.31 
0.30 

0.031 
0.017 

O.2I 
O    2O 

0.016 
o  017 

Powder  

96.61 

I   87 

o  70 

o  26 

O    I  <?7 

o  26 

O   OI  2 

Cubes  

97.  56 

2  .  IO 

o.  is 

o  08 

O   O22 

o  08 

O    O22 

Ferro-cobalt  

75.25 

O.6O 

21  .49 

1  .90 

o.  77 

O   OI4 

o  08 

O    OIO 

\ 

322  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

When  neutralizing  with  ammonia,  prior  to  adding  the  excess 
of  acetic  acid,  do  not  completely  precipitate  the  iron,  etc.,  but 
just  add  enough  ammonia  to  produce  a  slight  permanent  pre- 
cipitate. Then  redissolve  the  latter  in  acetic  acid  as  directed. 

Stellite.     Cobalt,  Molybdenum,  Iron,  Manganese,  Chromium. 

Dissolve  i  gram  and  800  mgs.  in  30  c.c.  cone.  HC1  and  30  c.c. 
cone,  nitric  acid;  evaporate  to  20  c.c. ;  add  100  c.c.  cone,  nitric  acid 
and  evaporate  to  dryness,  but  do  not  ignite,  as  cobalt  may  become 
insoluble.  Dissolve  in  50  c.c.  cone.  HC1;  evaporate  to  20  c.c.; 
transfer  to  1000  c.c.  boiling  flask;  and  dilute  to  200  c.c.  Perox- 
idize;  add  Na2O2  until  black  precipitate  forms  and  tends  to 
settle;  add  10  grams  more  of  peroxide  and  10  grams  Na2COs; 
bring  just  to  boil;  continue  to  boil  10  minutes;  cool;  filter  on 
double  15  cm.  papers  and  wash  with  peroxide  water. 

Redissolve  the  black  precipitate  in  60  c.c.  i  :  i  HC1;  and  pre- 
oxidize  again  as  before  and  so  on  until  nitrates  are  free  of  yellow 
color.  Three  peroxidations  are  sufficient.  Residue  on  filter 
is  cobalt  and  iron.  Dissolve  off  filter  as  before;  filters  are 
washed.  Ash  the  filters  and  extract  any  remaining  cobalt  with 
10  c.c.  HC1  and  add  to  main  cobalt  and  iron  solution.  Two 
basic  acetate  separations  are  made  of  this  solution  as  in  cobalt 
steel.  Then  finish  filtrates  by  phosphate  precipitation  as  in 
cobalt  steels.  The  acetate  of  iron  on  the  filter  can  be  dissolved 
in  HC1,  reprecipitated  and  weighed;  or  titrated  as  in  iron  ore. 

Chromium  is  obtained  as  in  chromium  ore,  except  that  the  iron 
and  cobalt  are  filtered  out  and  washed  with  sodium  peroxide 
wash.  Filtrate  and  washings  are  boiled  for  20  minutes  to  remove 
HzOz  and  titrated  with  ferrous  ammonium  sulphate  as  in  chrome 
ore. 

Molybdenum  is  gotten  from  a  separate  portion,  dissolving 
in  the  same  mixture  as  in  cobalt  steel.  The  molybdenum  is 
then  precipitated  as  in  steel  with  H^S. 

Manganese  is  determined  as  in  cobalt  steel,  removing  most  of 
the  cobalt  with  H^S. 

Silicon  is  found  by  fuming  with  sulphuric  acid,  as  in  chrome 


QUANTITATIVE  TESTS  FOR  COBALT  AND  NICKEL  IN  STEEL        323 
ANALYSIS  OF  STELLITE. 


Per  cent. 

Cobalt 60.80 

Molybdenum 24.10 

Chromium 13 . 20 

Manganese 0.55 


Per  cent. 

Iron 0.52 

Silicon 0.27 

Phosphorus 0.02 


OXYGEN  AND  SALTS  (SODIUM  CHLORIDE,  ETC.)  IN 
METALLIC  COBALT. 

The  oxygen  is  determined  on  the  finely  powdered  sample  as  in 
tungsten  (see  page  74). 

Salts  other  than  cobalt  salts  are  determined  by  extracting  the 
finely  divided  sample  by  boiling  it  in  distilled  water  in  a  platinum 
dish  until  the  decanted  extract  no  longer  leaves  a  residue  on 
evaporation.  The  extract  is  decanted  through  a  filter.  The 
combined  extracts  are  dried  at  120°  C.  and  weighed.  The  ex- 
tract is  then  dissolved  in  water  and  a  little  HC1,  if  necessary; 
made  very  faintly  ammoniacal  and  saturated  with  H2S.  Any 
precipitate  so  obtained  is  filtered  out;  washed  with  H2S  water; 
ignited  in  a  porcelain  crucible;  weighed;  and  deducted  from  the 
weight  of  the  extract  dried  at  120°  C.  The  following  is  an 
analysis  of  an  alleged  c.p.  metallic  cobalt  powder;  Co,  95.45  per 
cent;  Si,  o.oi  per  cent;  C,  0.25  per  cent;  chlorides,  other  than 
cobalt  salts,  1.89  per  cent;  O,  1.72  per  cent. 


CHAPTER  XV. 

PART  I. 
THE  DETERMINATION  OF  NITROGEN  IN  STEEL  AND  IRON. 

A  NUMBER  of  English  and  American  chemists  prefer  to  deter- 
mine the  nitrogen  in  steel  by  dissolving  it  in  i  :  i  HC1.  The 
nitrogen  is  supposed  to  exist  in  the  steel  as  Fe5N2  or  Fe4N2  and 
is  converted  into  ammonia  by  evolved  hydrogen.  This  ammonia 
then  combines  with  the  HC1  to  form  ammonium  chloride.  This 
solution  of  iron  chloride  and  ammonium  chloride  is  poured  into 
a  flask  of  the  style  shown  on  page  269  but  of  700  to  750  c.c. 
capacity.  A  double  bored  stopper  is  used  in  the  flask.  Through 
one  hole  is  passed  a  long  stemmed  separatory  funnel  whose  tube 
just  dips  under  the  fluid  in  the  flask  when  all  of  the  solutions 
are  in  it.  The  other  hole  in  the  stopper  is  for  a  glass  delivery 
tube,  one  end  of  which  just  passes  through  the  stopper  into 
the  flask  and  the  other  end  is  connected  with  a  glass  condenser 
of  the  Liebig  type.  Before  introducing  the  solution  of  the  sam- 
ple, 12  grams  of  NaOH  in  250  c.c.  of  water  are  put  in  the  flask; 
the  latter  is  connected  with  the  condenser;  and  about  half  of 
the  water  is  distilled  off  to  remove  any  nitrogen  that  may  be 
in  the  NaOH  before  the  actual  determination  of  that  in  the 
sample  is  begun. 

Having  purified  the  NaOH  from  any  nitrogen  it  may  contain, 
as  above,  the  i  gram  of  sample  which  has  meanwhile  been 
dissolved  in  20  c.c.  of  i  :  i  HC1  is  run  slowly  into  the  flask 
(which  is  first  connected  with  the  condenser)  via  the  separa- 
tory funnel.  When  all  of  the  solution  of  the  steel  is  in  the 
flask,  it  is  given  a  whirling  motion  to  mix  thoroughly  the  HC1 
solution  of  the  steel  with  the  NaOH.  The  mixture  is  then 
brought  to  a  boil,  and  the  boiling  is  continued  until  the  dis- 
tillate which  is  received  in  Nessler  tubes  no  longer  gives  the 

324 


THE  DETERMINATION  OF  NITROGEN  IN  STEEL  AND  IRON    325 

characteristic  brown  color  with  Nessler  solution.*  The  total  dis- 
tillate is  then  treated  with  2  c.c.  of  the  Nessler  reagent  per  each 
200  c.c.  of  distillate.  The  brown  colored  solution  so  obtained 
is  then  matched  against  standard  ammonium  chloride  which  is 
made  by  dissolving  0.0382  gram  of  this  salt  in  one  liter  volume 
of  water.  As  ammonium  chloride  contains  26.18  per  cent  of 
nitrogen,  0.0382  X  0.2618  equals  o.oio  gram  of  nitrogen,  hence 
i  c.c.  of  the  above  standard  is  equivalent  to  o.ooooi  gram  of 
nitrogen. 

The  most  convenient  way  to  make  this  comparison  is  as  fol- 
lows: Suppose  that  200  c.c.  of  the  distillate  were  obtained. 
This  would  then  be  treated  with  2  c.c.  of  the  Nessler  solution 
and  well  mixed  in  a  Nessler  tube  or  other  convenient  compari- 
son tube.  Then  place  200  c.c.  of  water  in  a  duplicate  com- 
parison tube  together  with  2  c.c.  of  the  Nessler  solution.  Next 
drop  from  a  burette,  with  constant  mixing,  into  this  Nessler 
solution  and  water,  some  of  the  standard  ammonium  chloride 
until  the  color  of  this  mixture  just  matches  that  of  the  distillate. 
Suppose  that  the  reading  of  the  burette  showed  that  it  required 
an  addition  of  35  c.c.  of  the  ammonium  chloride  standard  to 
produce  in  the  imitation  mixture  a  depth  of  color  equal  to  that 
of  the  distillate  obtained  from  the  steel;  this  gives  the  volume 
of  the  test  as  202  c.c.  and  that  of  the  standard  as  237  c.c.  As 
35  c.c.  of  the  standard  solution  of  ammonium  chloride  were 
required  then  the  distillate  must  contain  0.00035  X  202  -t- 
237  X  100  4-  i  or  0.029  Per  cent  nitrogen.  A  blank  deter- 
mination must  be  run  including  all  of  the  chemicals  and  opera- 
tions, and  any  nitrogen  so  obtained  must  be  deducted  from  that 
found  in  the  steel.  The  accuracy  of  the  manipulations  can  also 
be  tested  by  putting  a  measured  amount  of  the  ammonium 
chloride  standard  solution  through  all  of  the  operations,  and  any 
nitrogen  found  in  excess  of  that  added  in  the  form  of  ammonium 
chloride  should  equal  the  blank  determination. 

Ledebur  prefers  to  determine  nitrogen  in  iron  or  steel  by  dis- 

*  The  reaction  causing  the  brown  coloration  is  explained  by  the  following  equa- 
tion: 2(2KI,  HgI2)  +  NH3  +  3KOH  =  NHg2IH2O  +  ;KI  +  2H2O. 


326  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

solving  10  grams  of  the  sample  in  a  flask  similar  to  the  one  used 
in  the  foregoing  method,  using  120  c.c.  of  dilute  sulphuric  acid 
made  by  diluting  i  part  of  cone,  sulphuric  acid  with  4  parts 
of  water.  When  the  sample  is  entirely  dissolved,  the  flask  A, 
Fig.  23,  is  connected  to  a  duplicate  flask  E  containing  a  little 
water.  This  second  flask  is  in  turn  connected  with  a  nitro- 
gen bulb  F  approximating  very  closely  to  the  Volhard  nitrogen 
bulb.  The  Volhard  bulb  has  a  stopper  through  which  the  deliv- 
ery tube  from  the  second  flask  containing  a  little  distilled  water 
passes.  This  delivery  tube  dips  almost  to  the  bottom  of  the 
nitrogen  bulb  in  which  is  placed  exactly  25  c.c.  of  N/io  sulphuric 
acid.  100  c.c.  of  water  containing  40  grams  of  NaOH  are  poured 
through  the  separatory  funnel  into  the  solution  of  the  steel  in  A. 
The  mixture  of  hydroxide  of  iron  and  NaOH  is  boiled  gently  and 
at  the  same  time  a  stream  of  air  is  drawn  through  the  entire 
apparatus.  The  boiling  and  drawing  of  air  is  continued  for  an 
hour.  By  this  time  all  of  the  ammonium  sulphate  formed  from 
the  nitrogen  in  the  steel  is  supposed  to  have  been  converted  into 
ammonia  by  the  action  of  the  NaOH  and  been  drawn  over  into 
the  N/io  sulphuric  acid  in  the  nitrogen  bulb.  The  contents 
of  the  latter  are  then  titrated  with  N/io  NaOH  with  a  few  drops 
of  methyl  orange  for  an  indicator.  The  number  of  c.c.  of  the 
N/io  sulphuric  acid  found  by  this  titration  to  have  been  neutral- 
ized by  the  ammonia  coming  from  the  nitrogen  in  the  steel,  is 
multiplied  by  the  factor  0.001401  to  find  the  part  of  a  gram  of 
nitrogen  that  existed  in  the  10  grams  of  steel.  This  method  is  to 
be  commended  by  reason  of  the  fact  that  a  large  sample  can  be 
taken,  and  it  is  not  dependent  on  the  operator's  skill  in  matching 
colors. 

CALCULATIONS. 

The  factor  i  c.c.  of  N/io  sulphuric  acid  equals  0.001401  gram 
of  nitrogen  is  obtained  as  follows:  Since  i  c.c.  of  N/io  sulphuric 
acid  contains  0.0049038  gram  of  H2SO4,  and  this  acid  unites 
with  ammonium  hydroxide  according  to  the  equation  H2SO4  + 
2  NHiOH  =  (NH4)2SO4  +  2  H2O,  we  have  the  proportion  given 
below: 


THE  DETERMINATION  OF  NITROGEN  IN  STEEL  AND  IRON     327 

H2SO4  :  2  N  :  :  i  c.c.  N/io  H2SO4  :  X 

or 
98.08  :  28.02  ::  0.0049038  :  X 

or 
X =0.0014009  gram  of  nitrogen. 

Suppose  it  is  found  by  titration  of  the  25  c.c.  of  H2S04,  after  the 
absorption  of  the  ammonia  formed  from  the  nitrogen  in  the  steel, 
that  only  23  c.c.  of  the  N/io  NaOH  are  required  to  discharge  the 
pink  color  given  to  the  25  c.c.  of  the  N/io  H2S04  by  the  methyl 
orange.  This  would  mean  that  25  c.c.  less  23  c.c.  or  2  c.c.  of  the 
N/io  sulphuric  acid  had  been  neutralized  by  the  ammonium 
hydroxide  coming  from  the  nitrogen  in  the  steel  and  the  blank. 
If  there  were  no  deduction  for  a  blank  then  the  percentage  of 
nitrogen  found  would  be  0.001401  X  2  X  100  divided  by  10 
or  0.028  per  cent  nitrogen. 

NESSLER  SOLUTION. 

35  grams  of  potassium  iodide  are  dissolved  in  200  c.c.  of  dis- 
tilled water.  To  this  KI  is  added  a  saturated  solution  of  mer- 
curic chloride  until  a  faint  precipitate  is  obtained.  Next  add  160 
grams  of  potassium  hydroxide.  Dilute  to  one  liter  and  add  more 
of  the  mercuric  chloride  solution  until  a  small  permanent  pre- 
cipitate of  mercuric  iodide  forms  and  remains.  This  precipitate 
on  settling  should  leave  a  pale  yellow  supernatent  fluid  which  is 
supposed  to  become  more  sensitive  with  age.  It  gives  a  brownish 
yellow  tint  to  small  traces  of  ammonium  or  its  salts  in  solution. 
If  large  quantities  of  ammonia  are  in  solution  the  Nessler  reagent 
produces  a  precipitate. 

According  to  Braune  when  the  nitrogen  reaches  0.035  Per 
cent  in  the  high  carbon  steels  it  causes  serious  brittleness. 

It  is  very  necessary  in  making  nitrogen  determinations  to 
carry  out  the  work  in  a  room  free  from  all  ammonia  fumes.  The 
work  should  be  done  in  a  place  apart  from  the  other  laboratory 
work.  In  drawing  air  through  the  train  in  the  method  described 


328 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


by  Ledebur  it  would  seem  advisable  to  purify  such  air  by  passing 
it  through  a  wash  bottle  containing  some  dilute  sulphuric  acid, 
before  it  enters  the  boiling  flask. 

APPARATUS  OF  LEDEBUR  FOR  THE  DETERMINATION  OF 
NITROGEN  IN  STEEL. 

In  his  Leitfaden  fur  Eisenhutten-Laboratorien,  Ledebur  uses 
the  apparatus  shown  in  Fig.  23.    The  steel  is  dissolved  in  A  and 


FIG.  23. 


the  NaOH  is  introduced  through  B.  The  air  is  drawn  through 
A  and  £,  carrying  the  ammonia  formed  from  the  nitrogen  in 
the  steel  through  E  over  into  the  measured  amount  of  N/io 
sulphuric  acid  in  F  where  it  is  absorbed  and  determined  as 
already  described. 


CHAPTER  XVI. 
THE  ANALYSIS  OF  GRAPHITE  AND  GRAPHITE  CRUCIBLES. 

THE  total  carbon  is  determined  by  direct  combustion  in  the 
electric  furnace.  The  sample  is  reduced  to  sufficient  fineness 
to  pass  through  No.  n  bolting  cloth.  A  hardened  steel  mortar 
is  used  with  a  ball  pestle.  The  chamber  of  the  mortar  is  3^ 
inches  deep  by  if  inches  in  diameter.  The  total  thickness  of 
the  steel  block  is  4  inches.  The  pestle  fits,  exactly,  the  bot- 
tom of  the  mortar.  The  material  is  pounded  into  this  open- 
ing by  striking  on  the  end  of  the  pestle  with  a  hammer.  It  is 
then  taken  out  and  ground  in  an  agate  mortar  to  loosen  the 
mass  which  is  sifted  through  the  bolting  cloth.  The  portion 
that  does  not  pass  the  cloth  is  put  back  into  the  steel  mortar  and 
hammered  again,  and  so  on  until  the  sample  all  passes  through 
the  cloth. 

0.200  to  0.300  gram  of  sample  is  used,  and  it  burns  completely 
in  oxygen  in  the  electric  furnace.  Forty-five  minutes  elapse 
from  the  time  the  sample  is  put  in  the  furnace  until  the  absorp- 
tion apparatus  is  detached  for  the  final  weighing  of  the  carbon 
dioxide  formed.  The  weight  of  the  C02  multiplied  by  27.27 
and  divided  by  the  weight  taken  for  analysis  yields  the  exact 
carbon  in  the  sample. 

VOLATILE  MATTER. 

One  gram  of  sample  is  burned  in  a  platinum  crucible  with  a 
slow  stream  of  oxygen  passing  in  through  a  hole  in  the  lid  of  the 
same.  The  lid  is  removed  and  the  contents  stirred  with  a 
nickel  wire  at  intervals  of  about  twenty  minutes.  The  porcelain 
tube  of  a  Rose  crucible  is  used  to  conduct  the  oxygen  through 
the  hole  in  the  platinum  lid.  When  the  contents  of  the  crucible 
no  longer  lose  weight  the  ignition  is  stopped.  The  total  loss 

329 


330  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

of  weight  less  the  weight  of  carbon  by  combustion  equals  the 
volatile  matter  other  than  carbon,  such  as  water  and  sulphur. 

A  direct  determination  of  water  can  also  be  made  by  igniting 
the  substance  in  a  stream  of  air,  dried  by  passing  it  through  a 
jar  of  phosphoric  anhydride  such  as  is  used  in  the  carbon  com- 
bustion train.  (See  Fig.  7  (7),  page  211.)  The  sample  is  put 
in  a  clay  boat  and  heated  to  redness  in  a  porcelain  or  quartz 
combustion  tube.*  In  the  outlet  end  of  the  tube  is  attached, 
by  means  of  a  rubber  stopper  and  glass  tube,  an  absorption  jar 
containing  phosphoric  acid.  The  outlet  of  the  absorption  jar 
is  guarded  against  the  ingress  of  moisture  by  a  calcium  chloride 
tube  closely  filled  with  bits  of  stick  caustic  potash.  The  air  is 
drawn  through  by  a  suction  pump.  At  intervals  of  twenty 
minutes  the  heat  is  lowered,  the  passing  of  the  air  is  stopped 
and  the  absorption  jar  is  weighed.  It  is  attached  again,  the 
heat  raised  to  redness  for  another  twenty  minutes,  and  the 
weighing  is  again  made  as  before,  and  so  on  until  there  is  no 
more  gain  than  is  obtained  by  a  blank  test  carried  through  in 
the  same  manner.  The  total  increase  in  weight  of  the  phosphoric 
anhydride  less  the  blank  is  calculated  to  percentage  as  water. 

A  blast  lamp  flame  is  used  to  expel  the  carbon,  obtain  the 
ignition  loss,  and  the  ash  for  analysis.  The  ash  from  the  i 
gram  taken  for  ignition  loss  is  analyzed  for  its  various  constitu- 
ents exactly  as  a  clay.  It  is  fused  with  a  mixture  of  10  grams 
of  anhydrous  carbonate  of  soda  plus  one  gram  of  niter  in  a  plat- 
inum crucible.  The  melt  is  dissolved  out  with  water  in  a 
platinum  dish,  using  heat  to  hasten  the  solution.  The  water 
extraction  is  transferred  to  a  No.  6  porcelain  dish.  The  dish 
is  covered  with  a  watch  glass,  and  i  :  3  sulphuric  acid  is  allowed 
to  flow  down  the  under  side  of  the  lid  until  125  c.c.  in  all  have 
been  slowly  added.  The  acidulated  fusion  is  stirred  cautiously 
with  a  glass  rod  extending  under  the  cover.  The  solution  is 
heated  until  all  effervescence  is  over.  The  under  side  of  the 

*  The  apparatus  shown  in  photo  No.  i,  page  75,  or  Fig.  i  on  page  77,  omit- 
ting the  pyrogallic  solution,  and  passing  air  or  oxygen  through  the  apparatus 
instead  of  hydrogen,  can  be  used  for  this  determination. 


THE  ANALYSIS  OF   GRAPHITE  AND   GRAPHITE   CRUCIBLES       331 

cover  is  rinsed  off,  the  washings  flowing  into  the  dish.  The  con- 
tents of  the  latter  are  then  evaporated  to  thick  fumes  of  sulphuric 
anhydride.  Cool.  Add  enough  water  to  dissolve  the  sul- 
phates, heating  for  about  twenty  minutes.  Cool  again.  Add 
paper  pulp.  Filter  and  wash  with  i  :  10  sulphuric  acid.  Wash 
60  times,  allowing  each  washing  to  drain  off  before  the  next 
one  is  added.  The  residue  on  the  filter  is  burned  at  lowest 
possible  heat  until  pure  white.  The  heat  is  then  raised  to 
blast  for  ten  minutes.  The  crucible  is  cooled  in  a  desiccator 
and  weighed.  The  contents  are  blasted  again,  or  until  no  further 
loss  occurs.  A  few  drops  of  sulphuric  acid  are  added,  the  cru- 
cible is  filled  to  about  two-thirds  its  capacity  with  hydrofluoric 
acid  and  evaporation  in  a  good  draft  to  fumes  of  sulphuric  acid 
follows.  The  sulphuric  acid  is  driven  off,  the  crucible  is  heated 
to  bright  red  and  weighed  again.  The  loss  of  weight  is  the 
silica,  which  multiplied  by  100  and  divided  by  the  weight  taken 
yields  the  percentage  of  the  latter  oxide.* 

The  filtrate  from  the  silica  is  reduced  with  10  grams  of  zinc 
and  titrated  for  iron  with  potassium  permanganate  to  first  pink 
that  lasts  for  a  few  seconds.  The  iron  is  calculated  to  oxide. 

If  alumina  is  also  wanted,  the  filtrate  from  the  silica  is  first 
precipitated  in  a  No.  7  porcelain  dish  in  about  a  600  c.c.  volume 
with  the  faintest  possible  excess  of  ammonia  water  which  has 
been  filtered  free  of  any  sediment  or  scales  of  glass.  When  the 
solution  is  faintly  ammoniacal  it  is  boiled,  cooled,  and  ashless 
paper  pulp  added  in  sufficient  quantity  to  secure  rapid  filtration 
and  washing.  The  aluminum  and  iron  hydroxides  are  washed 
free  from  sulphates  with  ammonium  nitrate  water.  The  wash- 
ings are  tested  with  barium  chloride,  and  when  no  milkiness 
forms  in  the  former  on  addition  of  the  chloride,  the  precipitate 
is  given  ten  more  washings.  The  filter  and  precipitate  are 
burned  cautiously  in  a  weighed  platinum  crucible  after  first 

*  There  may  remain  in  the  crucible,  after  the  evaporation  with  HFL  and 
H2SO4,  and  the  ignition,  a  little  stain  of  iron  which  should  be  dissolved  in  a  little 
HC1,  evaporated  to  thick  fumes  with  a  few  drops  of  H2SO4,  and  added  to  the 
filtrate  from  the  silica  before  the  reduction  of  the  iron. 


332  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

drying  out  some  of  the  excessive  amount  of  water  held  by  the 
pulp.  The  paper  pulp  is  roasted  out  and  the  ash  ignited  to  a 
constant  weight  with  a  blast  lamp.  The  precipitate  is  calcu- 
lated as  alumina  plus  oxide  of  iron.  All  of  the  phosphorus 
present  in  the  graphite  will  be  counted  as  alumina  unless  it  is 
desired  to  separate  it.  In  that  event  the  solution  should  be 
divided  before  the  ammonia  precipitation  is  made.  Pour  it 
into  a  500  c.c.  flask.  Dilute  to  the  500  c.c.  mark  with  water. 
Mix  the  contents  thoroughly  and  pour  enough  of  the  latter  into 
a  250  c.c.  flask  to  fill  it  to  the  mark. 

This  gives  two  portions;  one  is  reduced  at  once  with  zinc  and 
titrated  with  permanganate  for  iron.  The  permanganate  stand- 
ard is  made  by  dissolving  0.727  gram  of  potassium  permanga- 
nate in  water  and  diluting  it  to  1000  c.c.  i  c.c.  of  this  standard 
equals  0.001284  gram  of  iron.  In  a  burned  pot  the  iron  is  cal- 
culated to  ferric  oxide.  Therefore  the  iron  found  in  parts  of  a 
gram  is  multiplied  by  10  and  divided  by  7  to  obtain  the  amount 
of  ferric  oxide.  It  is  necessary  to  make  this  calculation  in  all 
cases  where  alumina  is  asked  for.  In  plumbago,  or  graphite,  it 
is  usually  customary  to  calculate  the  iron  to  protoxide  (FeO). 
To  obtain  the  amount  of  the  latter,  multiply  the  weight  of 
metallic  iron  found  by  |.  These  weights  of  oxide  are  then  re- 
duced to  percentage  in  the  usual  way. 

PHOSPHORUS  AND  ALUMINA. 

The  other  250  c.c.  portion  of  the  divided  sulphate  filtrate  is 
precipitated  with  a  faint  excess  of  ammonia,  washed,  roasted, 
and  blasted  to  constant  weight  as  A12O3,  Fe2O3,  P2O5.  The  ferric 
oxide  found  in  the  250  c.c.  reduced  with  zinc  is  deducted  from 
the  total  weight  of  the  three  oxides  found  in  the  second  portion. 
This  leaves  A12O3,  P^O^.  The  phosphorus  is  obtained  by  fusing 
the  oxides  with  twenty  times  their  total  weight  of  sodium  car- 
bonate plus  four  times  their  weight  of  potassium  nitrate.  The 
melt  is  dissolved  in  a  few  c.c.  of  water,  filtered  into  a  5-ounce 
beaker,  washing  the  filter  thoroughly  with  ammonium  nitrate 
water.  The  filtrate  is  acidulated  with  i  .20  nitric  acid,  boiled  with 


THE  ANALYSIS  OF   GRAPHITE  AND  GRAPHITE   CRUCIBLES       333 

a  slight  excess  of  permanganate  solution  (see  Phosphorus  in 
Steel),  and  the  phosphorus  is  finished  as  in  steel.  The  phos- 
phorus obtained  is  calculated  to  the  pentoxide  (P2O5)  as  follows: 
For  example,  suppose  10  c.c.  of  the  alkali  standard  were  used,  then 
10  X  o.oooi  X  1.63  equals  0.00163,  which  multiplied  by  fy 
equals  the  phosphorus  pentoxide  to  be  deducted  from  the  weight 
of  A1203,  P205.  This  leaves  the  alumina  which  came  from  the 
0.500  gram  of  sample.  It  is  reduced  to  percentage  by  the 
usual  calculation.  If  phosphorus  is  not  asked  for,  it  is  unnec- 
essary to  divide  the  sulphate  filtrate  from  the  silica.  It  can  be 
precipitated  with  ammonia,  filtered,  washed,  roasted,  ignited, 
and  weighed  as  A12O3,  Fe203,  ignoring  the  presence  of  phosphorus, 
which  is  not  likely  to  introduce  a  serious  error.  The  total  oxides 
are  then  fused  with  10  grams  of  sodium  carbonate,  the  melt 
dissolved  in  excess  of  i  :  3  sulphuric  acid  (about  85  c.c.  of  the 
acid) ;  reduced  with  zinc  and  titrated  with  permanganate. 
The  iron  is  calculated  to  Fe2O3  and  deducted  from  the  A1203  and 
Fe2O3  to  obtain  alumina. 

LIME  AND  MAGNESIA. 

If  lime  and  magnesia  are  asked  for,  the  ash  from  the  graphite 
is  fused  as  before,  but  is  acidulated  with  an  excess  of  hydrochloric 
acid  instead  of  sulphuric  acid. 

The  silica  is  removed  by  evaporating  twice  to  hard  dryness 
and  filtering  between  evaporations.  It  is  washed  with  i  :  10 
hydrochloric  acid.  The  filtrate  and  washings  are  precipitated 
with  a  slight  excess  of  ammonia  that  has  been  freed  from  carbon 
dioxide  as  follows:  The  ammonia  water  is  put  in  a  sulphur 
flask  fitted  with  a  No.  6  stopper  through  which  passes  a  glass 
tube.  This  tube  is  connected  by  rubber  tubing  with  a  jar  such 
as  shown  in  Fig.  4,  page  209,  filled  with  short  pieces  of  stick 
caustic  potash.  The  connection  is  with  the  top  of  the  jar. 
The  ammonia  water  in  the  flask  is  heated  by  a  Bunsen  burner. 
This  drives  the  concentrated  ammonia  from  the  flask  over 
into  the  jar  of  caustic  potash,  which  removes  the  CO2.  The 
purified  ammonia  passes  out  at  the  bottom,  and  from  thence  via 


334  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

more  rubber  tubing  it  reaches  the  glass  delivery  tube,  which 
dips  into  a  reagent  bottle  containing  distilled  water  that  has  been 
boiled  for  half  an  hour  and  cooled  without  stirring.  The  am- 
monia is  passed  into  this  bottle  until  the  water  in  it  smells 
strongly  of  ammonia.  The  carbondioxide-free  ammonia  is  used 
for  all  separations  of  iron  from  lime. 

The  nitrate  from  the  iron  and  alumina  is  concentrated  to 
300  c.c.  and  made  faintly  ammoniacal.  If  the  presence  of  man- 
ganese is  suspected,  a  slight  excess  of  bromine  is  added,  and  the 
solution  is  heated  until  the  brown  flakes  of  manganese  separate. 
This  is  not  done  unless  the  carbonate  and  nitrate  fusion  of  the 
original  ash  is  noticeably  green. 

The  hot  faintly  alkaline  filtrate  is  treated  with  20  c.c.  of 
saturated  solution  of  ammonium  oxalate  to  precipitate  the  cal- 
cium as  oxalate.  The  latter  is  permitted  to  settle  several  hours. 
It  is  then  filtered  out  and  washed  with  hot  water  containing  a 
little  ammonium  oxalate,  until  free  of  chlorine  test  with  silver 
nitrate  solution.*  The  precipitate  is  roasted  until  white  and 
blasted  to  constant  weight.  It  is  weighed  as  calcium  oxide, 
which  is  calculated,  as  such,  to  percentage.  The  filtrate  from 
the  lime  is  acidulated  with  HC1,  concentrated  to  a  small  volume; 
filtered;  made  slightly  ammoniacal;  cooled;  10  c.c.  of  saturated 
solution  of  microcosmic  salt  are  added;  and  then  the  total 
volume  is  increased  one-fourth  with  concentrated  ammonia. 
After  thorough  stirring,  the  precipitate  of  ammonium  magnesium 
phosphate  is  permitted  to  settle  until  the  next  day.  It  is  filtered 
on  a  small  filter  and  washed  forty  times  with  a  mixture  of  one 
part  of  cone,  ammonia  and  three  parts  of  water.  It  is  then 
burned  at  a  low  red  heat  until  white,  and  weighed  as  magnesium 
pyro-phosphate,  which  contains  36.21  per  cent  magnesium  oxide. 

The  filtrate  and  washings  should  be  treated  with  more  phos- 
phate solution,  and,  if  an  appreciable  precipitate  forms,  it  is 
collected,  washed,  ignited,  weighed  and  added  to  the  principal 
residue. 

*  Acidulate  the  washings  with  a  few  drops  of  1.20  nitric  acid  before  testing 
for  chlorine. 


THE  ANALYSIS  OF   GRAPHITE  AND   GRAPHITE  CRUCIBLES       335 

SILICON  CARBIDE. 

When  complete  analyses  of  old  pots  that  present  a  green- 
colored  fracture  are  made,  the  analytical  data  will  give  evidence 
of  the  presence  of  silicon  existing  in  the  reduced  state,  that  is 
not  entirely  as  oxide.  If  the  silica,  alumina,  iron  oxide  and  lime 
obtained  are  calculated  as  such  and  to  their  sum  is  added  the  total 
carbon  as  found  by  the  RED  LEAD  process,  the  percentages  may 
reach  the  impossible  total  of  115.8  per  cent  in  some  instances. 
Such  pots  when  broken  present  a  greenish  fracture.  When  the 
writer  first  encountered  this  difficulty  he  was  somewhat  puzzled. 
Such  material  cannot  be  burned  free  of  black  or  grey  residue 
in  a  stream  of  oxygen.  This  is  characteristic  of  silicon  carbide. 
The  combination  will  not  yield  its  carbon  in  the  electric  furnace 
with  oxygen  alone.  It  decarbonizes  readily  if  burned  with  red 
lead.  For  carbon  0.300  gram  of  green  fracture  pots  is  burned 
with  4  grams  of  red  lead.  The  blank  due  to  the  red  lead  is 
deducted,  and  the  carbon  percentage  calculated  as  in  pots  free 
from  silicon  carbide.  The  ignition  loss,  which,  in  a  burned 
pot,  will  ordinarily  check  within  o.i  to  0.2  per  cent  of  the  red 
lead  result,  will  fall  below  the  total  carbon  as  much  as  6  or 
7  per  cent  in  the  old  pots  containing  the  silicon  carbide,  due 
to  the  fact  that  the  carbon  cannot  be  burned  out  of  the  silicon 
carbide  except  with  red  lead. 

The  writer  estimated  the  carbide  as  follows:  The  total  carbon 
obtained  by  red  lead  combustion  and  the  ignition  loss  obtained 
by  blasting  in  a  stream  of  oxygen  were  both  calculated  to 
a  i  gram  basis.  The  weight  of  carbon  by  ignition  loss  was 
deducted  from  the  weight  of  the  total  carbon.  The  remainder 
was  calculated  to  silicon  carbide.  Then  the  excess  of  per  cents 
above  100  per  cent  was  assumed  to  be  oxygen.  The  amount  of 
silicon' required  to  combine  with  this  oxygen  was  calculated. 
The  silicon  was  then  figured  to  carbide.  The  per  cent  of  carbide 
gotten  in  this  manner  checked  fairly  well  with  that  found  by 
calculating  from  the  difference  between  the  total  carbon  and 
the  ignition  loss.  The  silicon  required  to  combine  with  the 


336  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

silicon  carbide  found  was  calculated  to  silica  and  deducted  from 
the  total  silica.  The  carbon  remaining  after  the  ignition  in 
oxygen  was  deducted  from  the  total  carbon.  A  sample  analysis 
of  an  actual  case  is  appended. 

Per  cent. 

Free  carbon 38 . 92 

Silicon  carbide 20. 14 

Iron  oxide  (FeO) 4-37 

Alumina 15.11 

Free  silica 20 . 47 

Lime o.  98 

99-99 

Calculations  for  Silicon  Carbide. 

After  having  made  a  number  of  determinations  of  silicon 
carbide  in  old  pots,  with  green  fractures,  the  author  has  found 
it  more  satisfactory  to  obtain  the  total  percentage  footing  of 
the  oxides  and  carbon.  Assuming  the  excess  above  100  per 
cent  to  be  due  to  silicon  existing  as  carbide,  instead  of  oxide, 
the  calculations  are  as  follows: 

ANALYTICAL  DATA  (EXAMPLE). 

Per  cent. 

Total  carbon 44 . 90 

Total  "silica"  obtained 50.60 

Alumina 15.11 

Total  iron  calculated  as  protoxide  (FeO) 4.37 

Lime .98 

Total : 115.96 

Free  Silica.  This  gives  on  a  i  gram  basis  159.6  milligrams 
excess,  which  is  assumed  to  be  oxygen.  This  is  equivalent  to 
30.12  centigrams  of  silica: 

Si  +  O2  =  SiO2. 
O2  :  SiO2  :  :  O2  :  SiO2. 
32  :  60.4  :  -.159.6  :  x. 

x  =  30.124  centigrams  SiO2 

to  be  deducted  from  the  total  silica,  or  50.6  minus  30.124  equals 

20.47,  or  20-47  Per  cent  free  smca  m  tne  Pot- 

Silicon  Carbide.  Silica  is  reduced  to  silicon  by  the  factor 
0.4702,  therefore  the  30.124  centigrams  of  silica  correspond  to 


THE  ANALYSIS  OF   GRAPHITE  AND   GRAPHITE   CRUCIBLES       337 

30.124  X  0.4702  equals  14.16,  or  14.16  per  cent  silicon.    This 
is  equivalent  to  20.14  centigrams  of  silicon  carbide. 

Si  +  C  =  SiC. 
Si   :  SiC    :  :      Si    :  SiC. 
28.4  :  40.4  :  :  14.16  :    x. 
x  equals  20.14  or  20.14,  SiC  in  the  pot.  • 

Free  Carbon.  The  20.14  centigrams  of  silicon  carbide  cor- 
respond to  5.98  centigrams  of  carbon  to  be  deducted  from  the 
total  carbon  found: 

C  +  Si  =  SiC. 
C  :  SiC   :  :  C  :    SiC. 
12  -.40.4  :  :    x  :  20.14. 

x  equals  5.98,  or  44.90  minus  5.98  equals  38.92,  or  per  cent  of 
free  carbon  in  the  pot. 

RESULTS. 


Excess  of  Oxygen  Calculated  to  Silicon 
Carbide. 

Excess  of  Oxygen  Calculated  to  Silicon. 

Per  cent. 

38.92  carbon  (free) 
20.  14  silicon  carbide 
4.37  protoxide  of  iron 
15.  ii  alumina 
0.98  lime 
20.47  silica 

Per  cent. 

44.90  total  carbon 
14.  16  silicon 
4.37  iron  oxide 
15.  ii  alumina 
0.98  lime 
20.47  silica 

99.99 

99.99 

SULPHUR  IN  POTS  AND  GRAPHITES. 

Fuse  i  gram  of  sample  with  a  mixture  of  10  grams  of  sodium 
carbonate  ground  intimately  with  10  grams  of  potassium  nitrate. 
Such  a  mixture  must  be  heated  cautiously  as  it  will  flash  if 
heated  too  quickly.  When  the  first  action  is  over,  heat  until 
the  fusion  is  completely  molten  and  keep  it  so  with  the  least 
possible  heat  for  a  half  hour.*  Cool;  dissolve  the  melt  with 

*  With  the  present  high  price  of  platinum  it  would  be  advisable  to  determine 
the  sulphur  as  in  coke.  (See  page  403.) 


338  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

water;  acidulate  with  hydrochloric  acid  in  a  600  c.c.  casserole. 
Heat  with  cover  on  until  all  effervescence  is  over,  rinsing  same; 
evaporate  to  dryness  and  finish  as  sulphur  in  ferro-vanadium  of 
high  silicon  content.  If  such  a  fusion  is  heated  too  hot  it  will 
boil  out  of  the  crucible. 

STANDARDIZATION  OF  PERMANGANATE  FOR  IRON. 

Weigh  into  a  small  flask  0.062  gram  of  oxalic  acid  c.p.  Put 
into  this  flask  50  c.c.  distilled  water  and  20  c.c.  i  :  3  sulphuric 
acid.  Warm  the  solution  until  the  crystals  are  dissolved  and 
titrate  it  hot.  Do  not  let  the  solution  boil.  It  will  usually 
require  43.1  c.c.  of  this  permanganate  to  change  the  oxalic 
acid  solution  to  a  slight  pink.  Deduct  0.2  c.c.  blank.  There- 
fore 0.062  divided  by  42.9  X  8  divided  by  9  equals  0.001284 
or  i  c.c.  of  the  permanganate  solution  equals  0.001284  gram 
of  iron.  The  value  of  any  permanganate  solution  in  terms  of 
oxalic  is  multiplied  by  f  to  obtain  its  iron  value. 

For  a  check,  weigh  0.065  gram  of  oxalic  acid.  This  will 
require  45.2  c.c.  to  render  it  pink.  Therefore  0.065  divided  by 
45.0  X  8  divided  by  9  equals  0.001283,  or  i  c.c.  standard  solu- 
tion equals  0.001283  gram  of  iron. 

0.727  gram  of  KMn04  is  dissolved  in  i  liter  of  water  for  the 
above  standard, 


CHAPTER  XVII. 

PART  I. 
THE  ANNEALING  OF  STEEL. 

AFTER  several  years  of  experience  with  the  annealing  of  steel, 
during  which  careful  records  were  kept  with  a  Le  Chatelier 
pyrometer,  the  writer  came  to  certain  conclusions  as  to  the 
proper  temperatures  for  annealing  plain  carbon  steels  and  alloy 
steels. 

The  pyrometer  was  sent  to  the  bureau  of  standards  for  the 
verification  of  its  readings. 

Briefly  the  results  are  as  follows: 

ANNEALING  TEMPERATURES. 

First.  Cast  steel  of  all  kinds  that  has  never  been  reheated 
should  be  first  brought  to  a  temperature  of  850°  C.,  and  held 
there  for  one  hour.  The  heat  should  then  be  lowered  as  quickly 
as  possible  to  700  to  720°  C.  and  held  at  that  temperature  for 
ten  to  twelve  hours.  The  pipes  can  then  be  drawn  and  the  steel 
can  be  cooled  as  quickly  as  desired.  The  fact  is,  that  if  the 
steel  is  once  perfectly  annealed,  it  can  be  withdrawn  from  the 
furnace,  thrown  into  water  and  it  will  be  as  soft  as  ever. 
The  author  took  two  pieces  of  steel  from  the  same  saw  plate  and 
annealed  them,  one  lying  on  top  of  the  other,  until  he  knew  both 
were  perfectly  annealed.  He  then  withdrew  the  pieces  from  the 
furnace.  One  was  thrown  directly  from  the  annealing  furnace 
into  a  bucket  of  cold  water  while  still  at  the  annealing  heat. 
The  companion  piece  was  cooled  in  the  air.  Both  pieces  were 
then  pulled  in  the  testing  machine  and  registered  identically 
as  to  tensile  strength  and  elongation,  etc.  Steel  once  perfectly 
annealed  can  only  have  its  softness  impaired  by  heating  above 

339 


340  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

the  annealing  range.  Rapid  cooling  of  perfectly  annealed  steel 
has  no  effect  whatever  on  its  softness. 

However,  if  the  annealer  has  lowered  the  heat  before  the 
steel  has  been  entirely  annealed,  or  in  other  words  has  not  held 
it  long  enough  within  the  range  of  temperature  where  that 
particular  steel  anneals  most  quickly,  he  stands  a  better  chance 
of  getting  his  steel  eventually  soft  enough  for  the  purpose  in- 
tended by  burying  it  in  ashes  or  lime.  He  thus,  in  reality, 
holds  it  longer  within  the  range  of  temperature  where  steel 
anneals  slowly.  That  is,  the  steel  passes  more  slowly  through 
the  range  of  slow  annealing,  being  the  temperatures  below  720° 
C.,  than  if  it  had  not  been  surrounded  by  more  or  less  non-heat 
conducting  substances. 

Second.  The  author  has  found  that  plain  carbon  steels,  no 
matter  whether  the  carbon  be  0.50  per  cent  or  1.40  per  cent, 
anneal  best  and  most  quickly  between  700  and  720°  C. 

This  is  also  true  of  most  chrome-tungsten  and  chrome-molyb- 
denum steels.  It  is  particularly  noticeable  in  high  speed  steels, 
for  if  one  wishes  to  drill  a  high  speed  test  he  can  render  it  soft 
enough  by  annealing  it  for  one  hour  at  720  degrees,  whereas  it 
will  require  two  to  three  times  that  length  of  time  to  accomplish 
the  same  softening  at  lower  ranges. 

Third.  On  the  other  hand,  high  manganese  and  high  nickel 
content  lower  the  annealing  heat.  Seven  per  cent  nickel  steel 
anneals  to  the  perfectly  annealed  state  of  the  carbon  at  520  to 
550°  C.*  Again,  the  writer  has  succeeded  in  softening  Hadfeld's 
manganese  steel  so  that  it  could  be  drilled  without  dulling  a 
high  speed  tool  at  a  temperature  of  520  to  550  degrees.  The 
specimen  of  this  steel  that  the  writer  first  experimented  with 
was  of  the  following  analysis: 

Per  cent. 

Carbon i .  40 

Manganese 13-42 

Silicon 0.043 

Phosphorus o.  047 

Sulphur 0.030 

*  Read  remarks  given  on  page  347  on  the  annealing  temperatures  of  different 
alloy  steels. 


THE  ANNEALING  OF   STEEL  341 

Plates  of  this  steel,  before  annealing,  could  not  be  drilled 
even  with  a  high  speed  drill.  After  24  hours'  annealing  a  plate 
was  drilled  without  sharpening  the  bit  and  the  latter  drilled  the 
plate  without  "screeching."  In  fact,  four  holes  were  made  in 
such  a  plate  without  resharpening.  These  plates  were  then 
taken  to  the  planer  and  machined  easily,  but  they  presented 
the  peculiar  property  of  being  very  brittle.  The  condition  of  the 
carbon  by  the  acid  annealing  test  showed  that  the  carbon  had 
attained  almost  entirely  to  the  perfectly  annealed  state. 

Fourth.  Steel  that  has  been  reheated  and  rolled  or  ham- 
mered need  not  be  heated  above  720°  C.*  However,  if  the 
furnace  is  heated  to  850  degrees,  for  example,  and  a  lot  of  steel 
is  charged  into  it,  it  can  be  brought  to  720  degrees  more  quickly. 
The  large  body  of  cold  steel  will  absorb  its  surplus  heat. 

Overheated  Steel.  If  steel  ingots  are  allowed  to  lie  in  soaking 
pits  or  reheating  furnaces  at  temperatures  approximating  welding 
heats  for  considerable  time,  the  annealer's  task  will  be  greatly 
complicated,  as  such  steel  is  much  harder  to  bring  into  the  an- 
nealed state. |  Bad  cases  of  overheating  or  prolonged  soaking 
at  high  heats  will  require  two  or  three  times  as  long  to  anneal  at 
the  regular  temperature.  There  seems  to  be  nothing  to  do  in 
such  cases  but  to  re-anneal  until  the  carbon  is  finally  brought 
again  into  the  perfectly  annealed  condition. 

Fifth.  It  is  indeed  remarkable  that  plain  carbon  cast  steel 
as  it  comes  from  the  mold  can  be  refined  from  the  most  coarse 
crystalline  structure  ever  found  in  the  raw  cast  steel  to  a  fine 
silky  fracture  by  heat  alone,  before  it  is  hammered,  rolled  or 
forged  in  any  manner.  To  accomplish  this  great  change  it  is 
merely  necessary  to  heat  the  steel  first  as  it  comes  from  the 
mold  to  850°  C.  for  one  hour,  and  then  lower  the  heat  to  720°  C. 
and  hold  the  steel  at  this  temperature  for  twelve  to  fifteen  hours. 
Then  lay  it  out  to  cool  wherever  convenient.  A  complete  anneal, 
as  already  stated,  is  secured  in  this  manner. 

*  The  author  has  been  able  to  get  better  anneals  on  many  forged  chrome-tungsten 
steels  by  first  heating  the  same  through  for  an  hour  or  so  at  850  to  900°  C.  and  then 
holding  at  720°  C. 

t  By  reason  of  the  very  coarsely  crystalline  structure  formed  by  the  excessive  heat. 


342  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Sixth.  Steel  that  has  been  heated  to  800  to  850°  C.  and 
quenched  quickly  in  water  or  oil  will  attain  the  perfectly  annealed 
condition  within  thirty  minutes  to  one  hour's  time  at  a  temper- 
ature between  620  and  690°  C.,  whether  the  carbon  be  0.50  or 
0.90  per  cent,  that  is,  a  quenched  steel  anneals  at  a  lower  tem- 
perature than  when  unquenched,  and  in  less  time. 

FORMATION  OF  GRAPHITIC  CARBON  AND  BLACK  FRACTURE. 

On  three  different  occasions  the  writer  was  called  upon  to 
investigate  the  temperature  most  favorable  to  the  formation  of 
graphitic  carbon,  or  in  other  words,  to  ascertain  the  real  cause 
of  its  presence.  As  a  result  of  extended  experimental  annealing 
of  cold  rolled  steel  the  author  has  come  to  assign  the  cause 
largely  to  annealing  only,  within  a  range  of  temperature  that 
causes  the  carbon  to  assume  the  uncombined  state. 

As  mentioned,  on  three  different  occasions,  three  different 
lots  of  cold  rolled  steel,  coming  from  different  steel  works,  were 
subjected  to  prolonged  annealings,  and  the  progress  of  the  for- 
mation of  the  graphitic  carbon  was  noted. 

In  two  lots  the  cold  rolled  steel  was  free  from  even  traces 
of  the  graphite  at  the  beginning  of  the  anneals.  Anneals  were 
continued  in  some  instances  for  100  hours,  but  most  periods 
did  not  aggregate  over  40  hours.  Anneals  were  interrupted  at 
8-to  i2-hour  intervals  to  make  annealing  and  graphite  tests. 
Further,  a  1.30  carbon  tool  steel  ingot  was  put  in  a  lathe  and 
turned  down  until  there  was  nothing  left  of  it  but  a  f  inch 
rod.  By  prolonged  annealing  between  the  range  of  660  to  700 
degrees  black  fracture  was  produced.  This  was  raw  cast  steel 
that  had  never  been  hammered  or  rolled  or  forged  in  any  way. 
The  conclusions  are  as  follows: 

First.  The  higher  percentages  of  carbon  yield  the  black 
fracture  most  quickly,  the  range  from  1.20  per  cent  carbon  and 
above  being  the  most  favorable.  Percentages  under  i.oo  per 
cent  carbon  are  perhaps  free  from  appreciable  amounts  of 
graphitic  carbon,  at  least  under  any  conditions  likely  to  be  met 
with  in  practice. 


THE  ANNEALING  OF   STEEL  343 

Second.  The  temperature  most  favorable  to  the  quick  for- 
mation of  graphite  lies  between  660  and  700°  C. 

Third.  The  least  favorable  temperature  for  its  formation, 
within  the  annealing  and  cold  rolling  range,  is  below  600  degrees. 
The  other  extreme  of  temperature,  720°  C.,  is  also  less  favorable 
to  its  formation,  but  scaling  goes  on  so  fast  as  to  give  undesirable 
finish. 

Fourth.  The  reason  that  black  fracture  is  associated  with 
cold  rolling  is  that  during  this  process  the  steel  is  worked  and 
repeatedly  reheated  within  the  range  of  temperature  where 
graphite  forms  rapidly.  The  steel  has  really  had  a  series  of 
anneals  between  660  and  700°  C. 

Fifth.  The  longer  the  anneal  is  continued  at  any  annealing 
temperature,  the  more  graphite  will  be  formed. 

Prior  to  cold  rolling,  that  is,  when  the  steel  gets  its  very  first 
anneal  for  softening  purposes  only,  hold  it  at  700  to  720°  C. 
Keep  it  as  near  the  highest  annealing  heat  as  possible,  as  by  so 
doing  a  quick  anneal  is  obtained  without  formation  of  graphite. 

But  when  reheatings  occur  during  cold  rolling  do  this  re- 
heating at  the  lowest  heat  practicable,  for  around  580  to  600°  C. 
graphite  does  not  form  as  fast  as  at  660  to  700  degrees,  nor  does 
scale.  Let  the  periods  of  annealing  and  reheating  be  as  short  as 
possible. 

Sixth.  By  heating  steel  to  950  to  1000°  C.  for  one  or  two  hours, 
then  turning  down  the  gas  so  that  the  steel  cools  in  the  furnace 
to  660  to  700  degrees,  and  continuing  to  anneal  at  the  latter  tem- 
perature for  a  given  length  of  time,  graphite  can  be  eventually 
formed  in  steel  with  carbon  as  low  as  1.04  per  cent.  Therefore 
steel  that  is  to  be  cold  rolled  should  not  be  allowed  to  remain 
long  in  soaking  pits  or  heating  furnaces  at  high  temperatures. 

Steel  containing  chromium  is  not  likely  to  contain  graphite 
even  with  carbon  as  high  as  1.27  per  cent  and  chromium  as  low 
as  0.6  per  cent.  The  writer  succeeded  in  starting  a  graphitic 
formation  in  such  a  steel  only  by  heating  it  to  900  to  1000°  C., 
for  an  hour  or  two  before  annealing  at  660  to  700°  C.  In  neither 
this  instance  nor  in  the  case  of  the  1.04  carbon  plain  steel  did 


344  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

there  seem  to  be  any  appreciable  tendency  for  a  gradual  growth 
of  the  graphite  due  to  prolonged  annealing  only,  even  after 
the  eleventh  trial,  making  considerably  over  100  hours'  anneal. 
Perhaps  if  these  samples  had  been  again  heated  to  1000  degrees 
before  each  of  the  eleven  anneals,  an  appreciable  growth  of 
graphite  would  have  been  noted.  In  neither  instance  was  there 
enough  graphite  formed  to  be  noticeable  in  the  fracture. 

To  detect  small  amounts  of  graphite  dissolve  o.ioo  gram  of 
sample  in  a  152.4  mm.  by  16  mm.  tube  (6  inches  by  16  mm.) 
with  4  c.c.  1.20  nitric  acid  and  heat  on  a  water  bath  in  boiling 
water  for  two  hours  in  the  case  of  chrome  steel  and  one  hour  in 
plain  carbon  steel.  Permit  the  solution  to  stand  for  several 
hours  without  agitation  of  the  same  to  detect  traces  of  graphite 
which  can  be  plainly  seen  in  this  way  in  the  bottom  of  the  tube. 

ACID  TEST  FOR  ANNEALING. 

*  Dissolve  o.ioo  gram  of  sample  in  4  c.c.  of  cold  1.20  nitric  acid. 
Examine  immediately  in  daylight.     If  the  undissolved  carbon  is 
flaky  and  floats  about  in  the  solution  the  steel  is  not  annealed 
at  all.     It  is  in  the  condition  in  which  it  left  the  rolls  or  hammers. 
If  on  the  other  hand  the  carbon  is  in  an  extremely  fine  state  of 
division,  so  much  so  that  it  does  not  separate  in  flakes  at  all,  but 
rather  tends  to  run  up  the  sides  of  the  test  tube  in  a  thin  film, 
then  the  annealing  is  perfect  and  the  steel  has  reached  the  highest 
degree  of  softness. 

In  perfectly  annealed  steel  this  finely  divided  annealed  carbon 
will  remain  in  almost  complete  suspension  for  some  minutes. 
Indeed  it  cannot  be  seen  to  collect  and  settle  as  flakes,  but  settles 
imperceptibly,  after  some  time,  so  that  there  exists  a  collection 
of  fine  powder,  rather  than  flakes,  in  the  bottom  of  the  test 
tube.  An  ordinary  6  inch  by  1 5  mm.  carbon  test  tube  f  is  best 
suited  for  these  tests.  Then,  if  it  is  desired  to  examine  the 

*  Reject  surface  drillings  to  the  depth  of  at  least  |th  of  an  inch  when  taking 
a  sample  for  annealing  test. 

t  Test  tubes  must  be  scrupulously  clean,  free  from  the  slightest  film  of  grease, 
or  dirt,  or  other  coating. 


THE  ANNEALING  OF   STEEL  345 

sample  for  graphitic  carbon,  the  tube  is  put  at  once  on  a  water 
bath  in  boiling  water  for  one  hour.  By  that  time  all  of  the 
combined  carbon  will  have  gone  into  solution  and  the  graphite 
will  be  collected  in  a  coal  black  residue  in  the  bottom  of  the 
tube. 

The  operator  soon  learns  to  pronounce  to  an  absolute  cer- 
tainty whether  the  steel  is  perfectly  annealed  or  not.  He  also 
can  judge  whether  much  or  little  graphitic  carbon  is  present. 

This  annealing  test  is  carried  out  in  ten  minutes,  and  enables 
the  chemist  to  pronounce  unfailingly  on  the  quality  of  the  an- 
nealing before  the  steel  is  shipped  to  the  customer.  It  gives 
a  perfect  control  over  the  work  that  is  being  done  by  the  man  in 
charge  of  the  annealing.  A  scale  of  annealing  can  be  established. 
It  has  been  the  writer's  custom  to  call  perfect  annealing,  5 
degrees.  Good  enough  for  all  practical  purposes,  4!  degrees. 
Moderately  good,  4  degrees.  Partially  annealed,  3  degrees,  and 
so  on.  The  quicker  the  carbon  forms  in  flakes  and  separates, 
the  poorer  the  annealing.  As  stated,  good  annealed  carbon 
does  not  separate  in  flakes  at  all. 

ANNEALING  TEST  WHEN  ALLOYS  ARE  PRESENT. 

When  from  o.i  per  cent  to  i  per  cent  chromium  is  present 
in  steel  the  annealing  carbide  is  formed  and  acts  differently 
from  carbon  in  plain  steel.  It  forms  almost  coal  black;  is  not 
flaky;  but  the  individual  grains  are  coarser  than  in  plain  carbon 
steel. 

A  well  annealed  chrome  carbide  within  the  above  chromium 
content  forms  in  minute  coal  black  grains  that  settle  rapidly 
to  the  bottom  of  the  test  tube.  The  quicker  the  grains  form, 
the  blacker  they  are,  and  the  more  rapidly  they  settle  to  the 
bottom,  the  better  the  anneal. 

This  peculiarity  constitutes  an  infallible  test  for  the  presence 
of  chromium  in  steel,  but  the  latter  must  be  perfectly  annealed 
to  show  as  small  a  quantity  as  o.i  per  cent  chromium  in  o.ioo 
gram  of  sample.  More  experience  is  required  to  pronounce 
on  the  annealing  of  chrome  steel  by  the  acid  test,  but  with 


346  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

practice  one  can  be  quite  as  accurate  as  when  making  the  test 
on  plain  carbon  steel. 

In  well  annealed  steel  containing  3  per  cent  of  chromium  and 
over,  the  carbide  is  coal  black  but  does  not  settle  to  the  bottom 
nearly  so  fast  as  does  the  carbide  found  in  perfectly  annealed 
steel  of  i  per  cent  chromium  and  under.  The  grains  settle 
slowly,  and  there  is  a  well  denned  film  running  up  the  walls  of 
the  test  tube,  but  the  grains  should  be  in  the  finest  state  of 
division. 

Plain  tungsten  steel,  in  the  perfectly  annealed  state,  gives 
practically  the  same  appearance  as  ordinary  carbon  steel  when 
tested  for  annealing. 

Nickel  and  manganese  steels  act  exactly  as  plain  carbon  steel 
when  perfectly  annealed.  The  color  of  the  finely  divided  an- 
nealed carbon  has  perhaps  more  of  a  brown  shade  in  high  man- 
ganese and  nickel  steels,  but  it  does  not  settle  any  faster  than 
in  plain  carbon  steels.  One  of  the  greatest  difficulties  in  anneal- 
ing steel  is  to  obtain  uniform  heat  throughout  the  entire  furnace. 
The  dividing  line  between  a  good  annealing  heat  and  hardening 
temperature  is  very  sharp.  The  writer  has  had  a  piece  of  steel 
but  two  inches  long  exhibit  perfect  annealing  on  one  end,  while 
the  other  end  had  passed  into  the  hardening  range.  He  has  also 
another  piece  that  shows  black  fracture  on  one  end,  and  the  other 
end  less  than  two  inches  away  shows  no  trace  of  black  fracture. 
These  phenomena  are  due  to  unequal  temperature  in  the  furnace. 

An  annealing  furnace  should  have  several  pyrometer  couples 
located  in  different  parts  of  it. 

The  pyrometers  should  be  sent  to  the  Bureau  of  Standards 
for  occasional  verification  of  their  readings.  They  should  not 
be  used  until  their  accuracy  has  been  verified,  as  different  in- 
struments are  liable  to  disagree  as  much  as  25°  C.  from  the 
Washington  Standard. 


CHAPTER  XVII. 

PART  II. 

(i)  FURTHER  ANNEALING  TEMPERATURES. 
(2)   SURFACE  DECARBONIZATION. 

SUPPLEMENTING  the  annealing  temperatures  given  on  pages 
340  and  341  one  can  calculate  approximately  the  best  annealing 
temperature  for  manganese  and  nickel  steels  by  deducting  from 
720°  C.,  i8j  degrees  for  every  per  cent  of  manganese  or  nickel 
present;  and  on  account  of  the  similarity  of  cobalt  to  nickel  the 
presumption  is  that  the  rule  holds  good  for  cobalt  also.  To 
determine  exactly  the  best  annealing  temperature,  one  should 
first  determine  the  critical  point  of  the  steel  and  then  anneal  it 
just  under  the  critical  point  (Ar2).  If  one  has  no  apparatus  for 
critical  point,  then  recourse  can  be  had  to  the  above  calcula- 
tion. The  result  can  be  checked  by  the  acid  annealing  test 
given  on  pages  344  and  345  and  the  annealing  trials  continued 
until  the  chemical  test  shows  the  annealing  is  perfect. 

ANNEALING  TEMPERATURE  FOR  CHROME-MANGANESE 
STEEL  AND  CHROME-NICKEL  STEEL. 

In  such  steels  there  exists  two  independent  annealing  tem- 
peratures, that  is  the  steel  must  be  given  an  annealing  as  though 
it  were  chrome  steel  or  about  720°  C.  and  then  the  temperature 
should  be  lowered  and  the  steel  annealed  as  though  it  were  a 
manganese  steel,  or  a  nickel,  or  cobalt  steel,  only. 

Some  of  these  manganese-chrome  steels  require  as  low  as 
350  to  450°  C.  to  soften  the  manganese  combination  therein. 

12  per  cent  nickel  steel  of  low  carbon  (0.50%  carbon)  anneals 
well  at  about  500°  C.  Highly  alloyed  chrome- tungsten- vana- 
dium steels  with  carbon  over  i  per  cent,  alloyed  further  with 
2  or  3  per  cent  of  copper,  must  first  be  annealed  for  some  hours  at 
about  850°  C.  and  then,  curiously  enough,  must  be  given  as  low  an 

347 


348  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

annealing  as  though  10  to  13  per  cent  of  manganese  were  present. 
It  is  necessary  to  perform  the  annealing  in  this  way  before  the 
steel  can  be  drilled  at  all,  even  with  the  best  Rex  AA  drill.  The 
same  kind  of  a  steel  with  low  carbon  of  about  0.60  per  cent  C 
does  not  require  the  low  annealing  temperature.  This  is  a 
striking  example  of  the  fact  that  carbon  has  a  marked  influence 
on  the  annealing  temperature  in  some  cases.  It  no  doubt  has 
in  all  cases  but  the  writer  has  never  seen  such  marked  effect 
in  any  other  steels. 

THE  FORMATION  OF  "BARK"  OR  DECARBONIZED  SURFACE 
ON  PIPE-ANNEALED  STEEL. 

Several  years  ago,  since  the  publication  of  the  first  edition  of 
this  book,  the  author  investigated  the  cause  of  this  trouble- 
some soft  surface  and  his  conclusions  were  published  in  the  fol- 
lowing paper: 

THE  FORMATION  OF  WHITE  SCALE  ON  STEEL  AND  THE  SUR- 
FACE DECARBONIZATION  OF  PIPE-ANNEALED  STEEL.* 

BY  CHARLES  MORRIS  JOHNSON. 
Received  April   10,   1909. 

[Reprinted  from  the  Journal  of  Industrial  and  Engineering  Chemistry,  Vol.  I. 
No.  7.  July,  1909.] 

When  bars  of  steel  are  annealed  in  pipes,  with  charcoal,  to 
produce  a  scale-free,  frosted,  metallic  finish,  there  is  frequently 
found  at  the  surface  of  the  metal  a  coarsely  crystalline  structure 
H,  G,  Fig.  24,  that  is  much  lower  in  carbon  content  than  the 
remainder  of  the  bar.  Such  steel  will  not  harden  file-proof  on 
the  outside.  It  is  rejected  for  that  reason  by  makers  of  twist 
drills,  though  this  defect  be  so  slight  as  to  require  a  magnifying 
glass  for  its  detection. 

In  pipe-annealing  the  bars  are  put  in  a  steel  tube  that  is 
welded  shut  at  one  end.  The  spaces  between  the  pieces  are 
filled  in  with  wood  charcoal.  The  open  end  of  the  pipe  is  plugged 

*  From  a  paper  read  at  the  March,  1909,  meeting  of  the  Pittsburgh  Section  of 
the  American  Chemical  Society. 


SURFACE  DECARBONIZATION 


349 


350  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

with  fire  brick,  fire  clay  and  a  disc  of  plate  steel.  A  small  vent 
hole  is  located  at  one  end  of  the  pipe  to  permit  the  escape  of  the 
large  quantity  of  carbon  monoxide  that  is  generated  by  the 
reaction  between  charcoal  and  the  air  yet  remaining  in  the  vessel. 
As  apparently  dry  charcoal  often  holds  considerable  moisture 
in  its  pores,  some  water  vapor  must  also  be  liberated. 

The  superficial  decarbonization  G,  H,  7,  Fig.  24,  is  at  times 
much  more  pronounced  than  at  others.  The  writer  became 
interested  to  investigate  the  process  with  a  view  to  discovering 
the  primary  cause  of  this  very  objectionable  feature  of  annealing 
in  a  closed  tube. 

In  the  first  place  it  was  soon  noted  that  the  condition  fre- 
quently exists  in  steel  before  it  reaches  the  annealer,  due  to 
forging  at  too  high  temperatures. 

Again,  it  was  deemed  possible  that  the  scale,  always  existing 
on  the  steel  when  it  is  put  in  the  pipes,  might 'react  with  the 
charcoal  to  form  CO2.  Further,  that  the  latter  gas  would, 
under  the  existing  conditions,  decarbonize  the  steel  by  the  re- 
action CO2  +  C  =  2  CO. 

To  test  this  theory  some  f  inch  Rd.,  high  carbon  steel  rods 
were  placed  in  a  porcelain  tube  and  heated  for  18  hours  with  a 
slow  stream  of  pure,  dry  carbon  dioxide  passing  through  the 
enclosure.  The  following  points  were  noted: 

i  st.  A  glittering  black  scale  was  produced  on  the  fractured 
or  otherwise  unpolished  surfaces  of  the  bars.  On  fracturing 
the  latter,  a  distinct  ring  of  coarse  crystals  was  found  to  exist 
at  the  margin  of  the  fractures.  This  scale  has  a  curious  prop- 
erty of  adhering  in  a  thick,  sparkling  black  mass  on  rough 
fractured  surfaces,  but  when  polished  steel  is  exposed,  at  a  red 
heat,  to  the  attack  of  C02,  only  a  black  discoloration  resulted. 
The  scale  referred  to,  proved,  on  analysis,  to  be  Fe3O4.  This 
experiment  showed  that  carbon  dioxide  may  cause  "bark" 
(surface  decarbonization)  but  not  to  a  marked  enough  extent 
to  offer  a  satisfactory  explanation. 

2nd.  Some  pieces  of  the  same  bar  were  heated  in  a  stream  of 
pure,  dry  hydrogen.  A  frosted  metallic  surface  was  produced 


SURFACE  DECARBONIZATION  351 

and  also  a  slight  "bark."  Hydrogen,  therefore,  will  decarbonize 
steel  by  forming  hydrocarbons. 

3rd.  Next,  a  piece  of  the  bar  was  heated  in  the  closed  porce- 
lain tube,  packed  loosely  with  charcoal.  First  air  was  expelled, 
but,  as  the  heat  attained  slight  redness,  large  quantities  of  CO 
escaped  at  the  outlet  end.  After  an  18  hour  heating,  at  about 
750  to  780°  C.,  a  handsome  frosted,  metallic  surface  had  dis- 
placed the  black  oxide  and  much  decarbonization  was  noted. 
The  carbon  content  of  the  bar  before  annealing  was  1.08  per 
cent.  The  decarbonized  zone  yielded  but  0.84  per  cent. 

4th.  Thinking  that  CO  gas  might  be  the  active  agent  in  (3), 
a  small  clay  boat  was  filled  with  about  a  tablespoonful  of  char- 
coal. The  boat  was  then  placed  in  the  tube  with  a  piece  of  the 
steel  and  the  usual  period  of  heating  followed.  The  result  was 
the  same  as  in  the  third  experiment.  Note.  Annealing  in  a 
stream  of  natural  gas  produced  a  sooty  exterior  and  a  heavy 
"bark"  (see/,  Fig.  24). 

5th.  The  fourth  trial  suggested  annealing  a  piece  of  steel  in  an 
EMPTY,  CLOSED  TUBE  with  NO  CHARCOAL  or  other  reducing  sub- 
stance! No  attempt  was  made  to  remove  the  air  except  as  it 
was  partially  driven  out  at  the  vent  end  by  expansion.  The  only 
precaution  taken  was  to  prevent  indrawing  of  more  air,  at  any 
time,  while  the  tube  was  hot.  The  same  result  was  obtained  as 
is  shown  in  the  white  bars  at  C,  Fig.  25,  that  is,  an  aluminum- 
like  surface  with  great  decarbonization  underneath !  This  experi- 
ment was  repeated  with  steel  containing  but  o.io  per  cent  carbon 
and  also  with  steel  containing  large  quantities  of  chromium  and 
tungsten.  The  o.io  carbon  steel  is  given  at  B,  Fig.  25. 

The  writer  felt  that  he  had  now  reached  the  first  goal  and  that 
the  most  active  agent  in  surface  decarbonization  is  the  rust  or 
scale  which  is  actually  reduced  to  metal  at  the  expense  of  the 
carbon  in  the  steel  to  which  it  adheres: 

4  C  +  Fe304  =  3  Fe  +  4  CO. 

In  this  connection  the  question  arose,  would  steel  with  an 
extra  heavy,  loosely  adhering  scale  perform  in  like  manner?  Or, 


352 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


O 


SURFACE  DECARBONIZAT1ON  353 

in  other  words,  is  close  contact  necessary  for  reduction?  To 
settle  this  query  a  small  piece  of  quarter  octagon  of  saw  analysis 
was  given  a  prolonged  heating  in  an  open  muffle  at  about  850° 
C.  This  treatment  blistered  the  bar  with  a  thick  scale  that 
was  so  loose  that  the  sample  had  to  be  transferred  to  the  anneal- 
ing tube  quite  carefully  to  prevent  the  scale  from  being  jarred 
off.  After  15  hours'  heating  no  change  was  noted,  that  is,  the 
scale  was  still  black.  After  a  second  heating  of  18  hours  the 
surface  of  the  scale  presented  a  slight  greyish  caste.  After  a 
third  period  of  18  hours'  heating  it  was  found  that  the  heavy 
black  scale  was  gone  and,  in  its  place,  a  white,  loosely  adhering, 
aluminum-like  scale  existed  on  the  steel.  Here,  apparently, 
the  black  scale  had  begun  to  reduce  on  its  top  surface  first. 

This  fact  pointed  to  the  existence  of  a  reducing  gas  in  the 
tube. 

6th.  The  writer  then  placed  a  piece  of  high  carbon  steel  in 
the  tube,  together  with  a  porcelain  boat  containing  some  hard, 
semi-fused  iron  oxide  obtained  from  a  carbon  combustion  of 
steel  drillings  in  oxygen.  This  hard,  baked  mass  Z),  Fig.  24, 
was  given  18  hours'  heating  at  a  temperature  of  about  850  to 
900°  C.  The  porcelain  boat  was  removed  and  found  to  contain, 
instead  of  a  dense  baked  mass,  a  loose,  friable  substance,  and 
that  the  volume  of  it  exceeded  the  original  about  2^  times.  The 
steel  that  had  been  in  the  tube  was  then  fractured.  It  was 
exceedingly  tough  and  disclosed  a  heavy  surface  decarbonization 
G,  Fig.  24.  The  loose  sponge  of  oxide  was  put  back  in  the 
tube  with  a  fresh  piece  of  steel  and  given  a  second  heating. 
This  time  the  substance  E,  Fig.  24,  in  the  boat  had  become 
light  grey  in  color  and  was  no  longer  friable  but  was  now  adherent 
and  almost  sticky  in  its  clinging  fibers.  This  material  assayed 
98  per  cent  metallic  iron  and,  on  being  cut  with  a  knife  blade, 
presented  a  metallic  luster.  It  occurs  that  here  is  a  means  of 
preparing  pure  metallic  iron  from  pure  oxide  by  heating  it  in  a 
closed  tube  with  a  sealed  vent  (the  writer  used  concentrated 
sulphuric  acid  for  a  seal),  together  with  a  piece  of  low  sulphur, 
high  carbon  tool  steel.  Before  turning  off  or  lowering  the  heat 


354  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

it  is,  of  course,  necessary  to  close  all  vents  perfectly,  otherwise 
air  will  be  drawn  in  the  tube  and  metallic  iron  surfaces  will  lose 
the  aluminum-like  luster  and  become  blued.  Metallic  iron  so 
prepared  should  certainly  be  free  of  occluded  hydrogen,  which 
constitutes  an  objection  to  electrolytic  iron.  Some  specular 
iron  ore  was  ground  to  a  red  powder  and  then  reduced  to  a  grey 
powder  in  this  way. 

A  piece  of  steel  A,  Fig.  25,  that  had  been  lying  in  water  for 
weeks  and  was  covered  with  both  black  and  yellow  oxides  was 
heated  in  an  empty,  sealed  tube.  The  result  was  a  white  me- 
tallic surfaced  sample.  A  piece  of  blue  steel  was  heated  four 
hours  in  an  empty  tube  and  the  blue  surface  was  replaced  by  a 
white  aluminum-like  one. 

7th.  Further  experiments  developed  the  fact  that  this  scale 
forms  much  more  rapidly  at  high  temperatures,  that  is,  those 
above  700  degrees.  The  higher  the  heat  the  more  rapid  the 
transformation  from  rust  and  black  scale  to  the  white  and 
metallic  scale.  This  white  scale  takes  on  the  white  appearance 
long  before  it  is  entirely  reduced  to  metal.  The  author  has  had 
white  scale  that  would  be  brittle  and  grind  to  a  black  powder. 
However,  when  the  .reduction  is  complete  the  scale  is  no  longer 
brittle  and  cannot  be  powdered,  but  is  entirely  metallic  in  its 
properties. 

8th.  The  corollary  from  the  fact  that  white  scale  forms  more 
slowly  below  750°  C.  is  that,  at  still  lower  ranges,  perhaps  below 
650°,  it  may  not  form  at  all.  Further  experiments  covering  this 
point  will  be  made. 

gth.  By  annealing  steel  in  a  closed  tube  with  a  small  vent  to 
permit  egress  of  gases  but  sealed  against  ingress  of  air,  at  tem- 
peratures close  to  700°  C.,  the  surface  decarbonization  is  so 
slight  that  no  ring  of  coarser  crystallization  can  be  detected. 
Only  a  cupped  effect  can  be  noted  around  the  margin  of  the 
fracture  (see  F,  Fig.  24),  yet  such  steel  will  take  on  a  suggestion 
of  the  aluminum-like  finish.  Here  the  surface  decarbonization 
is  confined  to  the  thinnest  skin.  Such  steel  hardens  file-proof 
immediately  under  this  extremely  thin  zone. 


SURFACE  DECARBONIZATION  355 

loth.  By  annealing  steel  that  had  been  polished  free  of  all 
rust  and  scale,  in  a  tube  from  which  ALL  OXYGEN  had  been 
expelled  by  CO,  no  surface  decarbonization  was  noted  and  the 
steel  hardened  file-proof.  The  CO  was  generated  by  heating 
wood  charcoal. 

nth.  A  rod  of  polished  steel  was  dipped  in  a  solution  of 
copper  sulphate  until  it  was  plated  with  metallic  copper.  After 
heating  this  rod  in  a  closed  tube,  without  expulsion  of  the  air, 
for  a  few  hours,  the  rod  was  removed  from  the  tube  and  was 
found  to  be  coated  with  a  handsomely  appearing  metallic  copper. 
During  this  experiment  the  tube  was  sealed  against  ingress  of 
oxygen. 

1 2th.  By  heating  tungsten  trioxide  in  a  closed  porcelain 
tube,  and  together  with,  but  not  in  contact  with,  either  a  piece  of 
steel  or  steel  drillings,  the  writer  was  able  to  produce  metallic 
tungsten  powder  of  99.98  per  cent  purity.  The  temperature 
required  for  this  experiment  was  1100°  C.  The  tungsten  oxide 
was  in  one  porcelain  boat  and  the  steel  drillings  were  in  another. 


CHAPTER  XVIII. 

PART  I. 
THE  COMPLETE  ANALYSIS  OF  LIMESTONE  AND  MAGNESITE. 

(i)  DISSOLVE  0.9  or  i.o  gram  of  the!  sample  in  50  c.c.  of 
i  :  i  HC1  in  a  No.  5  (4!  inch)  covered  dish.  Boil  until  all 
action  is  over,  remove  the  cover  and  evaporate  to  dryness  on 
the  graphite  bath;  heat  until  the  smell  of  acid  is  practically  all 
gone.  Cool;  add  40  c.c.  of  i  :  i  HC1;  cover;  boil  with  the 
lid  on  and  evaporate  to  20  c.c.;  add  50  c.c.  of  water;  boil  with 
the  cover  on  for  a  few  minutes;  add  ashless  paper  pulp;  filter; 
wash,  first  with  dilute  i  :  40  HC1,  and  then  with  water  until  20 
drops  of  the  washings  do  not  give  even  a  slight  milkiness  with 
silver  nitrate  solution.  Smoke  off  the  paper  in  a  platinum  cruci- 
ble and  then  raise  the  heat  to  bright  redness  until  all  black  is 
gone  and  the  ash  in  the  crucible  is  from  a  pure  white  to  a  grey, 
depending  on  the  grade  of  the  limestone.  Weigh  the  ash  after 
it  has  been  cooled  in  the  desiccator  and  calculate  it  as  insolu- 
ble residue.  Fuse  this  insoluble  residue,  which  consists  of 
silica  contaminated  with  some  lime,  oxide  of  iron  and  magnesia, 
with  20  times  its  weight  of  anhydrous  sodium  carbonate;  dis- 
solve the  residue  out  in  water  in  a  platinum  dish  with  heat  or 
in  porcelain  in  the  cold  in  HC1  if  no  platinum  dish  is  available; 
acidulate  the  water  solution  with  an  excess  of  HC1;  heat  with 
the  lid  on  until  all  spraying  due  to  the  escape  of  carbon  dioxide 
is  over  and  evaporate  to  hard  dryness,  twice,  filtering  after  each 
evaporation.  Moisten  the  residue  in  the  dish  with  10  c.c.  of 
cone.  HC1;  heat;  add  50  c.c.  of  water;  boil  five  minutes;  add 
a  little  paper  pulp;  filter  and  wash  as  in  the  case  of  the  insol- 
uble residue;  ignite  until  the  ash  is  pure  white  and  weigh  as 
pure  silica.  As  an  extra  precaution  against  the  presence  of 
sodium  salt  it  is  more  accurate  to  volatilize  silica  as  in  steels 
with  HF1  and  a  few  drops  of  H2SO4,  page  286. 

356 


THE  COMPLETE  ANALYSIS  OF  LIMESTONE  AND  MAGNESITE      357 

(2)  The  filtrate  from  the  pure  silica  is  added  to  the  main 
filtrate  and  washings  obtained  from  the  insoluble  residue.  These 
combined  filtrates  contain  all  of  the  calcium,  magnesium,  iron 
and  aluminum.  A  slight  excess  of  ammonia  is  added  to  the 
nearly  boiling  filtrates  to  precipitate  the  iron  and  aluminum.  A 
little  paper  pulp  is  well  stirred  in;  the  hydroxides  are  filtered 
off;  washed  with  water,  redissolved,  and  precipitated  as  before 
to  insure  the  complete  separation  of  the  calcium  and  magne- 
sium. The  reprecipitated  iron,  etc.,  is  washed  free  of  chlorides 
with  water  and  ignited  to  a  constant  weight  in  a  platinum  cru- 
cible as  Fe2O3,  A1203  and  calculated  as  such  to  percentage. 

The  filtrates  from  the  double  precipitation  of  the  iron  are 
combined,  evaporated  to  600  c.c.,  heated  to  boiling,  and  the 
calcium  is  precipitated  with  50  c.c.  of  a  saturated  solution  of 
ammonium  oxalate.  This  amount  of  oxalate  is  added  not  only 
to  precipitate  the  calcium  but  to  insure  an  excess  of  the  oxalate 
in  sufficient  quantity  to  hold  the  magnesium  in  solution  as  the 
latter  is  soluble  in  an  excess  of  the  oxalate. 

The  oxalate  of  calcium  should  stand  for  at  least  several  hours 
when  it  is  filtered  off,  after  mixing  it  with  considerable  paper 
pulp.  Wash  it  with  oxalate  water  (5  grams  of  ammonium 
oxalate  dissolved  in  500  c.c.  of  water)  until  the  washings,  acidu- 
lated with  a  few  drops  of  nitric  acid,  fail  to  give  a  reaction  with 
silver  nitrate.  The  calcium  oxalate,  to  insure  against  the  co- 
precipitation  of  a  portion  of  the  magnesium,  should  be  dissolved 
in  HC1,  the  filter  thoroughly  washed  and  the  calcium  reprecipi- 
tated as  before,  this  time  adding  25  c.c.  of  the  ammonium 
oxalate.  The  reprecipitated  calcium  oxalate  is  filtered,  washed, 
ignited,  and  finally  blasted  to  constant  weight  as  calcium  oxide, 
which  weight  multiplied  by  1.7847  gives  the  equivalent  weight 
of  calcium  carbonate  which  is  calculated  to  percentage  as  such. 

The  filtrates  and  washings  from  the  two  precipitations  of 
the  calcium  oxalate  are  combined  and  evaporated  to  about  200 
c.c.  in  the  case  of  limestone,  or  to  about  400  c.c.  if  magnesite. 
The  solution,  which  should  contain  no  crystals,  is  made  slightly 
ammoniacal  and  20  c.c.  of  a  saturated  solution  of  microcosmic 


358 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


salt  are  added  if  the  sample  is  limestone;  if  it  is  magnesite,  50 
c.c.  of  the  latter  salt  are  used.  The  volume  is  then  increased 
one-third  with  strong  ammonia.  The  solution  and  precipitate 
are  given  a  prolonged  stirring,  especially  if  the  precipitate  is 
slow  in  forming.  After  twelve  hours  have  elapsed  the  ammo- 
nium magnesium  phosphate  is  filtered  off  and  washed  free  of 
chlorides  with  a  mixture  of  80  c.c.  of  cone,  ammonia,  400  c.c.  of 
distilled  water  and  5  grams  of  ammonium  nitrate.  The  washed 
precipitate  is  smoked  off  in  a  platinum  crucible  and  then  the 
heat  is  raised  to  bright  redness.  The  residue  in  the  crucible  is 
stirred  from  time  to  time  until  it  is  finally  pure  white.  It  is 
then  cooled  in  a  desiccator  and  weighed  as  magnesium-pyro- 
phosphate,  which  multiplied  by  0.7572  gives  the  equivalent  weight 
of  magnesium  carbonate. 

The  calcium  oxide  and  the  magnesium  pyrophosphate,  after 
having  been  ignited  to  a  constant  weight,  should  be  dissolved  in 
HC1  and  the  milligram  or  two  of  silica  that  is  almost  invariably 
present  should  be  filtered  off,  washed,  weighed  and  deducted 
from  the  calcium  oxide  and  the  magnesium  phosphate  before 
the  final  calculations  to  carbonate  are  made. 

The  filtrates  and  washings  both  from  the  calcium  oxalate 
and  the  ammonium  magnesium  phosphate  should  be  tested  in 
every  instance  with  further  additions  of  the  precipitants  to 
make  sure  that  precipitations  have  been  complete. 


SOME  ANALYSES  OF  LIMESTONE. 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5- 

No.  6. 

Calcium  carbonate  

Percent 
94.  2O 

Percent 
93.21 

Percent 
94.71 

Percent 
98.80 

Percent 
81.35 

Per  cent 
90.30 

Magnesium  carbonate 

I    ei 

i  44 

2  .02 

o.  26 

3.08 

1.86 

Oxides  of  iron  and  aluminum  
Silica  or  insoluble  residue  

O.O9 
4.l6 

3-20 
i.  80 

1.46 
1  .46 

O.26 
0.31 

3-12 
11.68 

2.46 
5.26 

Samples  Nos.  2,  3  and  4  are  good  limestones  for  basic  open  hearth  purposes, 
being  low  in  silica  and  over  93  per  cent  in  calcium  carbonate.  Nos.  i  and  6  are 
doubtful  and  No.  5  is  distinctly  bad. 


THE  COMPLETE  ANALYSIS  OF  LIMESTONE  AND  MAGNESITE      359 


SOME  ANALYSES  OF  MAGNESITE.     (Burned.) 


No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

No.  6. 

^Magnesium  oxide  (MigO)           .... 

Percent 
8<;.OQ 

Percent 
83.33 

Percent 
85.09 

Per  cent 
83.21 

Percent 
86.19 

Per  cent 
84.44 

Calcium  oxide  (CaO)            

3.88 

3.22 

3.88 

4.32 

2.60 

3.24 

Silica  (SiO2)                            

1.84 

1.16 

1.84 

3.00 

4-59 

6.00 

Oxides    of    iron    and    aluminum 
(Fe2O3,  A12O3)    

8.38 

8.22 

8.38 

8.92 

5.52 

5.90 

Ignition  loss 

t    06 

In  determining  the  magnesia  in  burned  magnesite  lime  and  fire-brick  multiply 
the  weight  of  Mg2P207  obtained  by  0.36206  to  obtain  the  equivalent  in  magnesia 
(MgO). 

FIRE-BRICK  ANALYSES.     (Silica  Brick.) 


No.  i. 

No.  2. 

Silica 

Per  cent 
06    12 

Per  cent 
0^-00 

Oxides  of  iron  and  aluminum 

2  .OO 

1  .  71 

Calcium  oxide                           .        

I-.5O 

1.88 

THE  VOLUMETRIC  DETERMINATION  OF  CALCIUM. 
The  calcium  oxalate  obtained  as  given  in  the  gravimetric 
method  is  washed  free  of  chlorides  with  water  alone.  The  oxa- 
late is  washed  off  the  filter  as  far  as  possible  with  a  fine  jet  of 
water  into  a  beaker.  The  oxalate  remaining  in  the  filter  paper 
is  dissolved  out  with  40  to  50  c.c.  of  i  :  3  sulphuric  acid  and  this 
acid  solution  is  allowed  to  run  into  the  beaker  containing  the 
main  oxalate  of  calcium.  The  filter  is  thoroughly  washed  with 

1  :  20  H2S04.     The  filtrate  and  washings  are  warmed  until  all  of 
the  calcium  oxalate  is  dissolved.     The  solution  is  then  diluted  to 
350  c.c.  with  water  and  heated  nearly  to  boiling  and  titrated  to  a 
faint  pink  with  N/io  KMn04,  i  c.c.  of  which  is  equal  to  0.0020035 
gram  of  Ca. 

(i)     CaC204  +  H2S04  =  CaS04  +  H2C2O4. 
By  (i),     i  Ca  equals  i  H2C2O4. 

By  the  equation  on  page  199/2  KMnO4  =  5  H2C204,  hence 

2  KMn04  =  5  Ca,  or  316.06  parts  by  weight  of  KMnO4  corre- 
spond to  200.35  parts  of  calcium,  or  3.16  grams  of  KMn04,  N/io 
dissolved  in  a  liter  volume  will  have  a  value  of  i  c.c.  equals 
0.002  gram  of  calcium. 


CHAPTER  XVIII. 

PART  II. 

THE  ANALYSIS  OF  OPEN  HEARTH  BOTTOM  SAND  AND 
FIRE-BRICK. 

THE  sample  is  ground  to  the  fineness  of  flour  in  an  agate 
mortar.  It  is  then  dried  for  one  hour  at  a  temperature  of  105 
to  110°  C.  While  the  dried  sample  is  still  warm,  it  is  put 
into  a  clean,  dry  glass  stoppered  bottle  where  it  is  cooled  before 
using,  i  gram  and,  for  a  check,  0.9  gram  are  taken  for  the 
analysis,  being  weighed  into  30  c.c.  platinum  crucibles  together 
with  10  grams  of  anhydrous  sodium  carbonate.  This  flux  is 
well  mixed  with  the  sample  by  stirring  it  with  a  wire.  The 
thorough  mixture  of  sample  and  carbonate  is  heated  gradually 
to  redness  and  kept  at  a  bright  red  heat  until  the  mass  in  the 
crucible,  which  should  be  in  a  molten  state,  is  in  quiet  fusion, 
that  is  with  no  bubbles  of  CO2  escaping. 

The  melt  is  then  cooled,  and  the  crucible  and  contents  are 
placed  in  a  platinum  dish,  containing  about  100  c.c.  of  water 
which  is  kept  just  below  boiling  until  the  fusion  is  dissolved, 
leaving  only  a  stain  in  the  crucible  and  a  floating  mass  in  the 
dish  which  should  be  free  from  grit.  The  dissolved  fusion  is 
then  transferred  to  a  600  c.c.  casserole  and  acidulated  with 
50  c.c.  of  cone.  HC1,  keeping  the  casserole  covered  with  a  watch 
glass  during  the  very  gradual  addition  of  the  acid.  (In  case  a 
platinum  dish  is  not  at  hand,  dissolve  the  fusion  in  a  casserole, 
in  an  excess  of  i  :  i  HC1.) 

The  crucible  in  which  the  fusion  was  made  is  warmed  with 
5  c.c.  of  i  :  i  HC1  in  it,  to  dissolve  the  traces  of  iron  that  still 
adhere  to  its  inner  walls.  These  cleanings  are  added  to  the 
main  part  in  the  casserole  which  is  now  warmed  with  the  cover 
on  until  the  carbon  dioxide  is  mainly  expelled.  The  watch  glass 

360 


THE  ANALYSIS  OF  OPEN  HEARTH  BOTTOM  SAND,  ETC.   361 

cover  of  the  casserole  is  rinsed  off  and  evaporation  to  dryness 
follows.  To  render  the  silicic  acid  insoluble,  the  dry  residue  in 
the  casserole  is  given  a  further  heating  at  a  temperature  of  about 
120°  C.  for  an  hour.  Care  should  be  taken  not  to  exceed  this 
temperature  to  avoid  the  possibility  of  loss  of  iron  by  vol- 
atilization of  its  chloride. 

The  thoroughly  baked  residue  is  cooled;  moistened  with 
cone.  HC1,  using  about  20  c.c.  of  the  acid,  to  dissolve  the  oxides 
of  iron  and  aluminum;  heated  with  the  cover  on  to  insure 
complete  solution  of  the  oxides;  warmed  with  200  c.c.  of  dis- 
tilled water  for  a  half  hour  with  frequent  stirring  to  secure  as 
nearly  as  possible  a  perfect  extraction  of  the  large  quantity 
of  sodium  chloride  formed.  Ashless  filter  pulp  is  added  to  the 
extraction,  after  it  has  been  cooled,  and  stirred  in  with  the  now 
insoluble  silicic  acid.  The  mixture  of  pulp  and  silicic  acid  is 
poured  on  a  double  15  cm.  filter,  that  is,  on  to  a  filter  consisting 
of  two  papers  folded  together.  Such  a  filter  will  invariably 
secure  more  rapid  and  perfect  filtration  in  the  long  run  than  a 
single  filter. 

The  pulp  and  precipitate  are  washed,  alternately,  with  water 
and  i  :  20  HC1  until  the  washings  are  free  from  iron  test,  no 
longer  giving  a  reddish  tint  with  potassium  sulphocyanate 
solution.  Then  the  washing  is  continued  with  cold  water  until  a 
few  drops  of  the  washings  no  longer  give  a  white  turbidity  with 
a  water  solution  of  silver  nitrate.  The  filters  and  pulp  are  then 
removed  to  an  air  bath  and  dried  at  120°  C.  until  most  of  the 
water  is  gone.  The  filtrate  and  washings  are  evaporated  to 
dryness,  warmed  with  acid,  leached  with  water,  filtered,  washed 
free  of  iron  and  chlorides,  as  before,  to  obtain  that  part  of  the 
silicic  acid  that  may  have  escaped  complete  dehydration  in  the 
first  evaporation. 

The  filtrate  and  washings  from  this  second  filtration  are  re- 
tained for  the  main  part  of  the  iron,  aluminum,  calcium  and 
magnesium.  This  filtrate  and  washings  for  reference  are  desig- 
nated as  A.  The  residues  on  the  filters  from  the  first  and  second 
evaporations,  after  having  been  freed  from  the  excessive  amount 


362  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

of  wash  water  retained  by  the  pulp,  by  drying  in  the  air  bath,  are 
placed  in  as  large  a  platinum  crucible  as  is  available  and  the 
volatile  matter  in  the  paper  is  smoked  off,  cautiously.  The 
crucible  is  then  brought  slowly  to  redness  and  the  heating  is 
continued  until  the  ash  in  the  crucible  is  pure  white.  The  blast 
is  applied  for  ten  minutes,  the  crucible  is  cooled  in  the  air  for  a 
moment,  and  placed  in  a  desiccator  until  entirely  cold,  when  it 
is  weighed.  The  crucible  is  blasted  again,  cooled  and  weighed 
until  a  weight  is  obtained  that  does  not  differ  from  the  last 
weight  more  than  0.0002  gram.  This  weight  is  taken  as  the 
final  weight  of  the  total  silica  together  with  a  few  milligrams  of 
the  Ca,  Mg,  Fe,  Al,  Ti,  and  a  little  of  the  sodium  salts  that  can- 
not be  entirely  washed  out.  The  true  silica  is  then  gotten  by  the 
loss  of  weight  by  volatilization  with  about  20  c.c.  of  hydrofluoric 
•acid  and  10  drops  of  cone,  sulphuric  acid,  as  in  steels.  The  HF1 
is  added  a  little  at  a  time  to  prevent  loss  by  too  violent  escape 
of  the  silicon  fluoride.  The  evaporation  is  carried  on  in  a  good 
draft  until  thick  fumes  of  the  sulphuric  anhydride  appear.  It 
is  advisable  to  evaporate  off  the  HF1  in  a  specially  prepared 
place  to  prevent  the  etching  of  the  hood  windows.  Such  an 
arrangement  can  be  built  in  a  wide  chimney  in  the  form  of  an 
arched  space.  The  writer  places  therein  a  large  agateware  pan 
filled  with  a  layer  of  graphite.  To  provide  a  clean  spot  on  which 
to  stand  each  crucible  a  number  of  nickel  disks  or  lids  of  nickel 
crucibles  are  arranged  on  top  of  the  graphite.  The  pan  is  heated 
with  a  Bunsen  burner.  About  two  feet  above  the  pan,  supported 
by  offsets  in  the  brickwork,  is  an  asbestos  board  J  inch  thick 
which  entirely  prevents  any  foreign  matter  from  falling  into  the 
open  crucibles  during  the  evaporations.  A  still  better  plan  is  to 
construct  a  small  reverberatory  furnace,  lining  it  with  asbestos 
board,  heating  it  from  above  by  a  flame  behind  a  bridge  wall. 
Of  course  such  a  furnace  is  never  allowed  to  get  above  a  drying 
heat  for  these  evaporations.  Fig.  26  shows  the  construction  of 
such  a  furnace,  which  with  natural  gas  and  compressed  air  can 
be  brought  to  1300°  C.,  or  can  be  kept  at  a  mere  desiccating  heat 
by  burning  a  small  yellow  flame  in  the  combustion  chamber  C. 


THE  ANALYSIS  OF  OPEN  HEARTH  BOTTOM   SAND,  ETC.      363 


When  the  fumes  of  sulphuric  anhydride  no  longer  appear, 
the  crucible  is  removed  from  the  drying  chamber  and  heated  to 


Vertical  Section 


Front  Elevation 


2-%  Rods 


37  long 


2-3'x  3"angles     5'0"  •• 
2-3  'x  3"  6'0"  " 

1-Bar  2!/2"x  &"x  4'0"  » 


All  X  ^ick 


%  thick 


'.  b? 


*4    i 


Plan 


Door  and  Frames 


FlG.  26. 


low  redness  only,  in  order  to  drive  off  any  remaining  sulphuric 
acid,  and  yet  not  hot  enough  to  volatilize  any  sodium  salts  that 
may  have  contaminated  the  silica  and  remained  behind  after  the 


364  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

latter  was  evaporated  away  as  fluoride.  The  crucible  is  then 
cooled  in  the  usual  way  by  placing  it,  while  it  is  still  warm,  in  a 
desiccator  and  then  weighing  it  when  cold.  This  weight  is  de- 
ducted from  the  previous  weight  of  the  crucible  and  its  contents 
obtained  by  blasting  to  a  constant  weight.  The  difference  so 
obtained  is  calculated  to  percentage  as  silica. 

If  the  analyst  wishes  to  be  entirely  certain  that  all  of  the 
silica  has  been  completely  removed,  he  should  repeat  the  evap- 
oration with  HF1,  using  but  10  c.c.  of  the  acid  and  also  10  drops 
of  the  H2SO4.  If  the  crucible  does  not  lose  any  weight  on  the 
second  evaporation  and  ignition  then  the  operator  has  proved 
the  work.  As  previously  stated,  the  residue  in  the  crucible, 
after  these  evaporations,  may  contain  traces  of  all  of  the  elements 
present  in  the  sand  except  silica.  Therefore,  the  residue  is 
fused  with  20  times  its  weight  of  the  sodium  carbonate  and  is 
dissolved  out  as  in  the  original  main  sodium  carbonate  fusion 
of  the  sample,  and  the  acidulated  fusion  and  the  cleanings  of 
the  crucible  are  added  to  filtrate  A  which  will  now  contain  the 
total  Ca,  Mg,  Al,  Fe  and  Ti  in  the  sand  or  brick. 

Filtrate  A  is  now  evaporated  to  350  c.c.,  heated  to  nearly 
boiling  and  filtered;  i  :  i  ammonia  is  added  to  it  until  it  smells 
slightly  but  distinctly  of  ammonia.  Much  excess  of  ammonia 
will  prevent  a  part  of  the  aluminum  hydroxide  from  precipi- 
tating. To  avoid  the  tedium  of  long  boiling,  add  the  slightest 
possible  excess  of  ammonia.  If  the  solution  smells  strongly  of 
ammonia,  then  the  excess  of  the  latter  should  be  neutralized 
with  some  HC1.  Having  the  conditions  of  alkalinity  just  right, 
the  solution  is  boiled  for  five  minutes,  the  beaker  is  removed 
from  the  fire  and  some  paper  pulp  is  stirred  in,  in  large  or 
small  quantity  according  as  the  precipitate  seems  large  or 
small.  The  precipitate,  which  will  contain  all  of  the  Fe,  Al,  Ti 
and  P  in  the  sample,  is  filtered  off  on  a  double  filter  and  washed 
with  a  solution  consisting  of  5  grams  of  ammonium  nitrate  dis- 
solved in  500  c.c.  of  water.  This  is  continued  until  the  washings 
do  not  give  the  test  for  chlorides  with  silver  nitrate.  The  precip- 
itate is  dissolved  off  the  filter  with  hot  HC1  and  reprecipitated 


THE  ANALYSIS  OF  OPEN  HEARTH  BOTTOM   SAND,   ETC.      365 

as  before  with  ammonia;  filtered,  and  washed.  The  second 
precipitate  is  burned  off  and  blasted  to  a  constant  weight  as 
in  the  case  of  the  silica.  The  weight  obtained  is  recorded  as 
Fe203,  A1203,  TiO2. 

The  combined  oxides  are  then  dissolved  by  prolonged  heating 
with  cone.  HC1,  and  if  any  white,  floating  residue  remains  in- 
soluble it  is  filtered  out;  washed  thoroughly  in  the  same  way 
as  the  main  silicic  acid,  weighed,  deducted  from  the  total 
weight  of  the  iron  oxide,  etc.,  and  added  to  the  total  silica.  The 
nitrate  from  this  milligram  or  two  of  silica  is  reduced  with 
stannous  chloride  and  the  iron  titrated  with  the  dilute  potassium 
dichromate,  page  186,  to  obtain  the  amount  of  iron  present. 
The  latter  is  then  calculated  to  ferrous  oxide,  FeO.  It  is  also 
calculated  to  Fe2O3  and  deducted  from  the  total  axides  of  iron, 
alumina,  etc.  The  remainder  is  calculated  to  percentage  as 
oxides  of  Al,  etc.  (A12O3,  Ti02,  etc.). 

The  filtrates  and  washings  from  the  two  precipitations  of  the 
iron  and  aluminum  are  analyzed  for  lime  and  magnesia  exactly 
as  directed  for  limestone,  beginning  at  the  point  where  the  com- 
bined filtrates  from  the  double  precipitations  of  the  iron  are 
combined,  heated  to  boiling,  and  the  calcium  is  precipitated 
with  a  saturated  solution  of  ammonium  oxalate,  the  only  differ- 
ence being  that  the  lime  content  is  only  a  per  cent  or  two  so  that 
but  25  c.c.  of  the  ammonium  oxalate  are  used  to  precipitate  the 
calcium  present. 

The  ignition  loss  is  obtained  by  blasting  i  gram  of  the  sample 
to  a  constant  weight.  The  first  weight  is  taken  after  10  minutes' 
blasting.  The  sample  is  then  blasted  for  five-minute  intervals, 
until  it  either  no  longer  loses  more  than  0.0002  gram  or  begins  to 
gain  weight. 

When  analyzing  sand  or  brick,  blanks  should  be  run  includ- 
ing the  fusing  of  20  grams  of  the  carbonate  of  sodium  and  the 
putting  of  the  solution  of  this  melt  through  every  operation. 
The  iron,  silica,  etc.,  so  found  should  be  deducted  from  that 
found  in  the  sample.  There  is  almost  certain  to  be  some  iron 
and  silica  obtained  from  the  chemicals  and  glassware. 


366 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


Some  Analyses  of  Sands. 

No.  i. 

No.  2. 

No.  3. 

No.  4. 

No.  5. 

Ignition  loss      

Percent 
0.40 

Percent 
0.47 

Per  cent 
1  .20 

Percent 
0.64 

Percent 

Silica      

08.08 

95.86 

94.00 

96.86 

95.86 

Oxides  of  iron   aluminum,  etc 

I    37 

2    84 

4  4 

2    22 

4  86 

Calcium  oxide 

O.I1? 

0.^8 

Sand  No.  i  is  not  suitable  for  open  hearth  bottoms  as  it  does  not  bond  well 
with  the  bottom  but  floats  into  the  slag  and,  as  a  result,  the  steel  bath  cuts  through 
the  bottom  in  places.  No.  3  is  a  good  sand  as  it  contains  just  about  the  right 
amount  of  oxides  of  iron,  etc.,  to  bond  well.  No.  5  should  also  be  a  good  bottom 
sand. 

TITANIUM. 

Titanium  is  a  frequent  constituent  of  fire  brick.  The  best 
way  to  determine  this  element  is  to  obtain  the  total  iron  and 
aluminum  from  a  separate  one-gram  portion.  The  hydrochloric 
solution  of  this  iron,  etc.,  is  then  fumed  with  60  c.c.  of  i  :  3 
sulphuric  acid  and  this  residue  is  then  analyzed  as  given  for 
titanium  either  by  color  or  gravimetrically  as  in  steels. 


CHAPTER  XVIII. 

PART  III. 
THE  ANALYSIS  OF  IRON  ORE. 

Metallic  Iron.  Dissolve  0.400  and  0.500  gram  of  the  floured 
sample  (dried  at  105°  C.)  with  mild  heating  in  40  c.c.  of  cone. 
HC1  until  the  insoluble  residue  is  white  and  floating  and  free  from 
any  dark  colored  grit.  When  the  insoluble  portion  shows  no 
further  change,  the  total  sample  is  transferred  to  a  porcelain  dish 
and  evaporated  to  dryness,  in  case  the  insoluble  part  is  not  pure 
white.  This  evaporation  must  be  done  under  mild  heat  to  insure 
against  volatilization  of  iron  chloride.  Redissolve  with  20  c.c. 
of  cone.  HC1,  using  heat  and  keeping  the  dish  covered.  Add 
50  c.c.  of  water,  stir  in  a  little  ashless  paper  pulp  filter,  wash 
with  dilute  HC1  until  the  washings  are  free  of  iron  test  with 
KCNS.  The  filtrate  and  washings  will  contain  all  of  the  iron 
if  the  residue  was  pure  white  before  the  evaporation;  but  if  it  is 
the  least  bit  colored  there  is  possibility  of  it  retaining  some  of  the 
iron.  It  is  at  all  times  advisable,  for  close  work,  to  burn  the  paper 
off  until  all  black  due  to  carbon  is  gone  and  then  fuse  the  ash  with 
twenty  times  its  weight  of  sodium  carbonate  at  a  bright  red  heat 
for  a  half  hour.  This  renders  all  of  the  iron,  in  the  shape  of  silicate 
or  titanate,  soluble  in  HC1.  The  fusion  is  then  dissolved  out 
with  a  little  water,  an  excess  of  HC1  is  added,  and  the  solution 
is  evaporated  again  to  dryness,  redissolved,  filtered  and  washed 
exactly  as  described  for  the  original  main  sample.  This  filtrate 
and  washings  will  contain  all  of  the  iron,  if  any,  that  remained 
in  the  original  insoluble  portion;  it  is  added  to  the  first  main 
filtrate  and  washings  obtained  after  the  first  evaporation  to  dry- 
ness.  These  combined  filtrates  and  washings  are  concentrated 
to  200  c.c.  and  heated  to  nearly  boiling  in  a  beaker.  Stannous 
chloride  is  added  a  drop  at  a  time,  with  stirring,  until  the  hot 

367 


368  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

solution  is  water  white,  and  then  not  more  than  2  or  3  drops  in 
excess.  Place  the  600  c.c.  beakers  in  cold  water  until  room  tem- 
perature is  attained.  Then  as  each  test  is  about  to  be  titrated, 
add  to  it  40  c.c.  of  mercuric  chloride  solution  and  stir  well. 
This  should  produce  a  silky  white  precipitate  of  mercurous  chlo- 
ride, taking  care  of  the  excess  of  the  tin  chloride.  It  is  undesir- 
able to  have  a  large  excess  of  the  tin  chloride  as  there  is  danger 
of  producing  a  grey  precipitate  of  metallic  mercury  which  renders 
the  titration  inaccurate ;  and  again  a  huge  precipitate  of  mercur- 
ous chloride  is  undesirable. 

The  solution  being  properly  reduced,  it  is  titrated  with  a  stand- 
ard solution  of  recrystallized  potassium  dichromate,  until  two  or 
three  drops  of  the  solution  of  the  ore  no  longer  give  a  blue  spot 
test  with  the  ferricyanide  indicator  but  an  orange  color,  instead. 

REDUCTION  BY  METALLIC  ZINC  AND  TITRATION  WITH 
POTASSIUM  PERMANGANATE. 

After  getting  the  ore  in  perfect  solution  by  any  of  the  fore- 
going means,  the  solution  is  converted  to  sulphates  by  evapora- 
tion to  thick  white  fumes  with  80  c.c.  of  i  :  i  H2SO4.  The  iron 
sulphate  is  then  dissolved  again  by  heating  to  boiling  for  some 
time  with  100  c.c.  of  water.  The  solution  is  transferred  to  an 
800  c.c.  cone  flask  and  diluted  to  200  c.c.  A  stream  of  C02  is 
passed  through  the  flask.  A  total  of  40  grams  of  zinc  are  added 
in  portions  to  reduce  the  ferric  iron.  Heat,  when  the  action  of 
the  zinc  becomes  slow,  and  continue  to  pass  the  CO2  until  the 
zinc  is  all  dissolved.  Cool  to  room  temperature  with  the  C02 
passing.  The  C02  is  purified  by  passing  through  two  wash 
bottles  as  illustrated  on  page  295,  photo  No.  21. 

A  blank  of  the  same  amounts  of  sulphuric  acid  and  zinc  should 
be  run.  In  a  blank  the  solution,  toward  the  last,  is  very  slow, 
and  when  there  remains  only  about  0.5  gram  of  zinc,  undissolved, 
the  heat  can  be  shut  off  and  the  solution  cooled;  a  stopper  is 
placed  rather  loosely  in  the  flask  and  the  latter  is  then  let  stand 
at  room  temperature  until  the  next  day,  when  the  zinc  will  have 
completely  dissolved  and  the  blank  can  be  titrated  and  deducted. 


THE  ANALYSIS  OF  IRON  ORE  369 

The  iron  can  be  reduced  with  aluminum  as  described  for  uranium 
on  page  296. 

In  these  titrations  the  end  point  is  taken  as  the  first  pink 
color  that  spreads  entirely  through  the  solution  and  lasts  but 
a  few  seconds. 

The  permanganate  can  be  standardized  by  putting  a  similar 
weight  of  the  "Sibley"  iron  ore  standard  through  all  of  the 
operations,  or  with  sodium  oxalate,  or  with  oxalic  acid,  as  given 
on  page  49. 

(1)  It  would  seem  convenient,  at  this  point,  to  give  the  reac- 
tions involved  in  the  method. 

(2)  The  reaction  between  the  ferrous  iron  and  the  die hr ornate 
proceeds  as  follows:   K2Cr207  +  6  FeCl2  +  14  HC1  =  2  KC1  + 
2  CrCls  +  6  FeCl3  +  7  H20. 

(3)  The   following  equation   explains   the   reduction  of  the 
ferric  chloride  by  the  stannous  chloride:    SnCl2  -f  2  FeCla  = 
2  FeCl2  +  SnCl4. 

(4)  The  excess  of  the  stannous  chloride  is  prevented  from 
interfering  with  (2)  by  the  mercuric  chloride  reacting  to  form 
mercurous  chloride:  SnCl2  +  2  HgCl2  =  Hg2Cl2  +  SnClj. 

(5)  If  too  great  an  excess  of  the  stannous  chloride  is  present, 
a  grey  precipitate  of  metallic  mercury  is  produced  which  ren- 
ders the  titration  inaccurate  and  the  analysis  must  be  repeated 
on  a  new  portion:  Hg2Cl2  +  SnCl2  =  SnCLi  +  2  Hg. 

STANDARD  AND  SOLUTIONS. 

The  dichr ornate  is  made  by  dissolving  4.9  grams  of  the  recrys- 
tallized  salt  in  water  and  diluting  to  one  liter. 

The  stannous  chloride  is  made  by  dissolving  12.5  grams  of 
granulated  tin  in  125  c.c.  of  cone.  HC1  or  20  grams  of  the  stannous 
salt  in  100  c.c.  of  the  cone.  HC1. 

The  mercuric  chloride  consists  of  50  grams  of  the  salt  dissolved 
in  one  liter  of  water. 

The  ferricyanide  for  the  spot  test  has  a  concentration  of  0.5 
gram  per  100  c.c.  of  water  and  should  be  made  as  used. 


370  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

STANDARDIZATION. 

The  standardization  is  best  effected  by  putting  0.3  and  0.4 
gram  of  the  U.  S.  standard  "Sibley"  iron  ore,  or  some  other 
ore  that  has  been  standardized  with  equal  care  (this  latter 
standard  is  very  convenient  in  that  it  is  entirely  soluble  in  HC1), 
through  all  of  the  foregoing  operations  and  noting  how  many 
cubic  centimeters  of  the  dichromate  standard  are  required  to 
oxidize  the  known  amounts  of  the  iron  standard.  By  so  doing, 
an  average  value,  for  example,  of  i  c.c.  of  the  standard  equals 
0.00546  gram  of  metallic  iron  was  obtained. 

Manganese.  Dissolve  o.ioo  and  0.050  gram  of  the  powdered 
ore  in  25  c.c.  of  cone.  HC1.  For  close  work  filter  out  any  in- 
soluble matter,  wash  it  and  fuse  as  described  under  the  deter- 
mination of  metallic  iron.  Dissolve  out  the  fusion;  acidulate 
it  with  HC1  and  add  this  now  completely  decomposed  residue  to 
the  main  solution;  add  to  the  latter  20  c.c.  of  i  :  i  H2S04  and 
evaporate  to  thick  fumes;  cool;  add  20  c.c.  of  cone,  nitric  acid 
and  20  c.c.  of  water  and  heat  until  all  of  the  iron  and  manganese 
sulphates  are  dissolved  and  nothing  remains  but  the  floating 
silicic  acid.  Then  transfer  from  the  porcelain  dish  to  a  cone 
flask,  or  a  10  X  i  inch  test  tube,  rinsing  with  1.20  nitric  acid, 
and  finish  as  in  steels.  (See  page  276.) 

If  the  manganese  exceeds  2  per  cent,  i.o  and  0.9  gram  are 
gotten  into  solution  as  above  and  the  analysis  can  be  finished  by 
the  phosphate  method  or  by  the  ferricyanide  titration,  page 
1 88  or  page  193. 

Phosphorus  and  Silica.  Dissolve  0.9  and  i.oo  gram,  as  for  the 
metallic  iron,  using  40  c.c.  of  cone.  HC1,  fusing  the  insoluble 
residue  and  placing  the  acidulated  melt  back  in  the  main  solution; 
then  evaporate  to  dryness;  adding  i  gram  of  chlorate  of  potas- 
sium before  evaporating,  heating  with  the  cover  on  the  porcelain 
dish  until  all  action  caused  by  the  addition  of  the  chlorate  is 
over.  After  the  evaporation  to  dryness,  redissolve  in  20  c.c.  of 
cone.  HC1;  evaporate  to  10  c.c.;  add  20  c.c.  of  water;  add  a 
little  ashless  filter  pulp;  filter  and  wash  with  i  :  40  HC1  until 


THE   ANALYSIS  OF  IRON  ORE  371 

the  washings  no  longer  give  an  iron  test  with  KCNS;  evaporate 
the  filtrate  and  washings  again  to  dryness  on  the  graphite,  dis- 
solve, dilute,  filter  and  wash  as  before  to  insure  the  separation 
of  all  of  the  silica.  The  filters  from  the  first  and  second  evapora- 
tions to  dryness  contain  the  total  silica  and  are  ignited  and 
finished  for  silica  as  in  steel  (page  286). 

The  filtrate  from  the  second  filtration  and  washing  contains 
all  of  the  phosphorus;  it  is  evaporated  low  and  is  converted  to 
nitrates,  boiled  with  permanganate,  and  finished  for  phosphorus 
as  in  steel  (page  258). 

Sulphur.  Fuse  i.o  and  0.9  gram,  as  given  for  ferro-vanadium 
at  the  bottom  of  page  17,  running  blanks  as  a  check  on  the 
reagents. 

Aluminum,  Calcium  and  Magnesium.  Get  0.9  or  i.o  gram 
into  solution  and  evaporated  to  dryness  as  for  silica.  The 
filtrate  from  the  second  evaporation  will  contain  all  of  the 
aluminum,  iron,  manganese,  most  of  the  titanium,  all  of  the 
phosphorus,  calcium  and  magnesium.  Make  a  double  basic 
acetate  precipitation  of  the  filtrate  as  described  on  pages  188 
and  189  and  combine  the  two  sets  of  filtrates  and  washings  for 
the  calcium  and  magnesium.  The  precipitate  from  the  second 
basic  acetate  precipitation  is  burned  off  at  a  low  heat,  blasted  to 
constant  weight,  and  weighed  as  A1203,  Fe203,  TiQj,  P205.  The 
residue  in  the  crucible  is  then  dissolved  in  cone.  HC1  and  divided 
into  two  parts;  the  phosphorus  is  determined  in  the  one  part 
after  converting  it  into  nitrate  as  described  under  phosphorus; 
and  in  the  other  part  the  metallic  iron  is  found  as  given  under 
metallic  iron,  by  reducing  this  half  with  stannous  chloride.  The 
iron  so  found  is  calculated  to  Fe203,  multiplied  by  two  and  de- 
ducted from  the  total  weight  of  the  oxides.  In  the  same  way 
the  phosphorus  found  is  calculated  to  P205,  multiplied  by  two 
and  deducted.  This  leaves  only  the  weight  of  the  A12O3  and 
Ti02.  The  latter  is  determined  on  a  separate  portion  and  cal- 
culated to  a  one-gram  basis  and  deducted,  leaving  the  aluminum 
only. 

Also  these  same  weights  of  ore  can  be  gotten  into  solution 


372  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

as  for  silica,  the  silica  filtered  off;  the  filtrate  and  washings 
therefrom  can  be  transferred  to  a  i  liter  boiling  flask  and  the 
iron,  manganese  and  titanium  can  be  removed  by  two  or  three 
peroxidations.  The  filtrates  and  washings  from  peroxidations 
can  then  be  made  acid  and  the  aluminum  precipitated  at  once 
with  ammonia;  redissolved  and  reprecipitated  to  remove  the 
sodium  salts  that  are  inevitably  present  in  the  aluminum 
hydroxide.  The  reprecipitated  aluminum  hydroxide  is  weighed 
as  A12O3,  P2O5.  The  phosphoric  anhydride  is  determined  by 
fusing  the  two  oxides  in  20  times  their  weight  of  anhydrous  so- 
dium carbonate ;  the  melt  is  dissolved  in  nitric  acid  and  is  then 
evaporated  to  40  c.c.  and  finished  as  in  steels,  page  258. 

This  latter  scheme  is  decidedly  to  be  preferred  if  calcium 
and  magnesium  are  not  needed. 

Calcium  and  Magnesium.  The  filtrates  from  the  two  basic 
acetate  precipitations  are  combined  and  evaporated  nearly  to 
crystallization  with  100  c.c.  of  cone.  HC1.  Then  200  c.c.  of 
water,  or  more,  are  added  and  heat  is  applied  until  the  salts 
are  all  dissolved.  If  any  dirt  or  dust  has  crept  into  the  solution 
the  same  is  filtered  out  and  the  filtrate  and  washings  are  finished 
for  Ca  and  Mg  as  in  limestone  from  the  point  where  the  filtrates 
from  the  iron  have  been  obtained  and  are  ready  for  the  addition 
of  the  oxalate.  (See  page  357.) 

Also,  if  it  is  desired  to  obtain  the  latter  elements  in  a  separate 
portion  one  can  proceed  exactly  as  given  for  limestone  (page  356). 

Titanium.  Fuse  i  gram  with  20  grams  of  acid  potassium 
sulphate  and  finish  for  titanium  as  directed  on  page  51,  if  the 
titanium  content  of  the  ore  amounts  to  more  than  one  per  cent. 
If  the  per  cent  of  titanium  is  less  than  one  per  cent,  fuse  as 
above  but  boil  the  sulphuric  acid  solution  of  the  fusion  obtained 
as  directed  on  page  54  with  some  strong  nitric  acid  and  compare 
it  with  an  iron  ore,  containing  a  known  amount  of  titanium,  that 
has  been  put  through  all  of  the  operations.  Dilute  the  sulphuric 
acid  solution  of  the  fusion  to  100  c.c.;  boil  it  five  minutes  with 
25  c.c.  of  cone,  nitric;  cool  and  compare  as  given  for  steels  on 
page  54. 


THE  ANALYSIS  OF  IRON  ORE  373 

Copper  and  Nickel.  Dissolve  the  ore  as  far  as  possible  with 
HC1,  using  20  c.c.  of  the  cone,  acid  per  gram,  heating  a  little 
below  boiling  in  an  800  c.c.  beaker  until  the  insoluble  residue 
does  not  show  any  further  change,  that  is,  does  not  grow  any 
whiter.  Use  15  grams  of  the  finely  ground  sample  if  the  copper 
and  nickel  do  not  exceed  one  per  cent.  When  the  HC1  is  ap- 
parently having  no  further  effect,  then  add  cautiously  10  c.c.  of 
cone,  nitric  per  gram  of  ore  taken  and  also  a  total  of  10  c.c.  of 
hydrofluoric  acid  and  digest  the  contents  of  the  beaker  for  at 
least  one  hour. 

Evaporate  to  moist  dryness,  but  do  not  bake  for  fear  of  render- 
ing the  nickel  insoluble;  redissolve  in  100  c.c.  of  HC1  and  evapo- 
rate until  the  solution  does  not  seem  to  have  a  great  excess  of 
HC1;  convert  the  solution  to  nitrate  by  evaporating  until  fur- 
ther additions  of  cone,  nitric  acid  no  longer  produce  red  fumes 
or  until  a  few  drops  of  the  solution  give  but  little  if  any  milkiness 
with  silver  nitrate  solution.  Then  finish  for  copper  and  nickel  as 
given  on  pages  149  to  152.  Run  as  a  standard  an  iron  ore  con- 
taining a  known  amount  of  copper,  or  if  such  a  standard  is  not 
at  hand,  then  add  to  the  ore  a  known  amount  of  copper  and 
nickel  and  also  run  the  same  ore  without  any  copper  and  nickel, 
performing  the  standardization  in  the  same  way  as  given  for  pig 
iron  on  pages  149  and  151. 

Chromium.  Determine  the  chromium  exactly  as  given  for 
chrome  ore  on  pages  140  and  141. 

Ignition  Loss,  Carbon  Dioxide  and  Moisture.  The  ignition 
loss  is  obtained  by  heating  i  gram  of  the  sample  at  a  bright  red 
heat  for  an  hour. 

Carbon  dioxide  and  organic  matter  can  be  determined  together 
as  C02  by  burning  i  gram  of  the  sample  in  the  electric  combus- 
tion furnace  for  one  hour  in  a  stream  of  oxygen  as  in  steels. 
The  CC>2  existing  as  such  can  be  determined  by  heating  the  ore 
with  cone.  HC1.  in  a  flask  through  which  a  constant  stream  of 
air  purified  from  CO2  in  the  same  manner  as  the  oxygen  is  puri- 
fied for  the  determination  of  carbon  in  steel,  is  drawn.  The 
flask  should  be  provided  with  a  No.  6  rubber  stopper.  The 


374  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

flask  shown  for  sulphur  work  on  pages  104  and  269  will  answer. 
The  stopper  should  be  pierced  with  a  funnel  tube  as  shown  on 
page  104;  also  an  inlet  tube  for  the  purified  air  which  should 
extend  f  inch  below  the  acid  in  the  flask;  the  stopper  must 
also  have  an  outlet  tube  extending  through  the  stopper  into 
the  flask,  but  not  touching  the  fluid  in  the  same.  This  tube 
will  conduct  away  the  CO%  liberated  by  the  digestion  with 
HC1  by  means  of  gentle  suction  with  a  water  pump  connected  to 
the  outlet  of  the  weighing  apparatus.  The  weighing  apparatus 
and  the  train  between  it  and  the  outlet  of  the  digesting  flask 
can  be  made  exactly  as  the  same  part  of  the  carbon  combustion 
apparatus.  The  whole  apparatus  can  be  thought  of  as  parallel 
to  the  carbon  outfit  with  the  flask  taking  the  place  of  the  electric 
furnace.  If  it  is  more  convenient  oxygen  can  be  forced  through 
the  apparatus,  during  the  digesting  period,  instead  of  drawing 
air  through  the  outfit.  The  weighing  apparatus  /,  page  224, 
should  be  weighed  after  air  or  oxygen  has  been  drawn  through 
it  during  an  hour's  digestion.  /  is  again  attached  and  air  passed 
through  it  for  another  half  hour,  but  during  this  second  pas- 
sage of  the  air,  or  oxygen,  no  heating  should  be  necessary.  If 
there  is  no  more  gain  of  weight  than  a  blank  gives  at  this  point, 
then  it  is  proven  that  all  of  the  CO2  has  been  drawn  over  into 
the  weighing  apparatus.  The  operator  can  check  his  apparatus 
and  the  accuracy  of  his  manipulations  by  determining  the  CO2 
in  limestone  containing  a  known  amount  of  calcium  carbonate 
or  by  taking  a  known  weight  of  calcite  crystals. 

The  Moisture  is  determined  by  weighing  i  gram  of  the  sample 
and  drying  it  to  a  constant  weight  at  105°  C. 

Combined  water  is  determined  as  in  an  unburned  crucible, 
page  330,  using  i  gram  of  the  sample  that  has  been  already 
dried  for  one  hour  at  105°  C.  and  kept  in  a  glass-stoppered 
bottle  after  the  drying. 

Vanadium  is  determined  in  the  same  manner  as  given  for 
carnotite  ore,  page  301. 


CHAPTER  XVIII. 

PART  IV. 
THE  ANALYSIS  OF  FLUORSPAR. 

EXACT  METHOD. 

As  this  mineral  is  not  completely  decomposed  by  fusion  with 
sodium  carbonate  alone,  it  is  the  general  practice  to  fuse  the 
finely  ground  mineral  with  a  mixture  of  sodium  and  potassium 
carbonates,  and  finely  ground  precipitated  silica.  The  author 
uses,  for  the  melt,  an  intimate  mixture  of  i  gram  of  the  sample 
with  10  grams  of  each  of  the  two  carbonates  mentioned,  together 
with  3  grams  of  precipitated  silica. 

The  i  gram  of  the  spar  is  stirred  carefully  through  the  flux 
in  a  thirty-gram  platinum  crucible  and  the  whole  is  gradually 
brought  to  a  bright  red  heat  and  held  at  this  temperature  until 
all  bubbling  due  to  the  evolution  of  CO2  ceases,  indicating  that 
the  reactions  are  complete  as  follows: 

3  CaF2  +  3  SiO2  =  CaSiF6  +  2  CaSi03  (i) 

CaSiF6  +  4  Na2CO3  =  CaC03  +  Na2SiO3  +  6  NaF  +  3  CO2.     (2) 

When  the  fusion  is  finished  in  the  manner  indicated,  it  is  run 
around  the  sides  of  the  crucible;  and,  when  cooled,  the  crucible 
is  placed  in  a  platinum  dish  and  its  contents  dissolved  in  water 
with  heat.  I!  no  platinum  dish  is  available,  then  the  melt  must  be 
dissolved  in  the  cold  in  a  porcelain  dish.  When  all  is  dissolved 
except  the  floating  portion,  cool,  add  paper  pulp,  filter  into  a 
large  casserole  and  wash  the  residue  on  the  filter  with  2  grams 
of  sodium  carbonate  dissolved  in  500  c.c.  of  water,  giving  the 
filter  at  least  50  washings,  obtaining  residue  R  on  the  filter, 
and  the  filtrate  and  washings  A ,  which  latter  will  contain  all,  or 
nearly  all,  of  the  fluorine  as  NaF  and  much  silicic  acid  as  sodium 
silicate,  according  to  (2). 

375 


376  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  main  silica  in  nitrate  A  is  separated  according  to  the 
method  of  Berzelius,  by  heating  with  ammonium  carbonate 
and  removing  the  last  traces  with  an  ammoniacal  solution  of 
zinc  oxide  as  follows:  20  grams  of  ammonium  carbonate,  in 
powdered  form,  are  added  to  A  and  the  same  is  heated  for  an 
hour  at  40°  C.  A  is  then  filtered  after  12  hours.  Consider- 
able ashless  filter  pulp  is  stirred  in  with  the  precipitated  silicic 
acid.  The  mixture  of  pulp,  silicic  acid  and  perhaps  some  iron 
and  aluminum  hydroxides  is  filtered  out  and  washed  with  one 
gram  of  ammonium  carbonate  dissolved  in  500  c.c.  of  water,  at 
least  fifty  times,  allowing  each  washing  to  drain  off  completely 
before  the  next  one  is  applied.  This  filtrate  and  washings  can 
be  designated  as  B  and  contain  the  major  part  of  the  sodium 
fluoride  and  still  some  of  silicic  acid.  The  mixture  of  pulp  and 
silicic  acid  on  the  filter  from  A  can  be  marked  M . 

The  residues  R  and  M  are  smoked  off  in  a  large  platinum 
crucible  and  then  the  heat  is  raised  until  the  ash  is  free  of  char- 
coal and  of  a  light  brown  color.  In  this  way  nearly  all  of  the 
original  added  silica  is  returned  to  aid  in  attacking  any  unde- 
composed  spar  that  may  have  escaped  decomposition  in  the 
original  fusion.  Place  on  top  of  the  ash  from  R  plus  M  a 
ground  mixture  of  10  grams,  each,  of  the  carbonates  of  sodium 
and  potassium.  Stir  this  flux  all  through  the  ash  R  plus  M 
with  a  stout  Ni-Chrome  wire  and  then  repeat  the  fusion  as  de- 
scribed in  the  first  place,  and  all  of  the  other  foregoing  opera- 
tions. The  water-insoluble  residue  R'  from  the  second  fusion 
is  washed  with  sodium  carbonate  water  as  in  the  case  of  R. 
This  water-insoluble  residue  R'  contains  all  of  the  calcium, 
barium,  magnesium,  iron  and  some  of  the  aluminum.  The 
filtrate  and  washings  from  R'  contain  any  remainder  of  the 
fluorine  and  nearly  all  of  the  silicic  acid  and  aluminum  (if  Al  be 
present).  This  filtrate  and  washings  are  heated  with  ammonium 
carbonate  as  in  A,  allowed  to  stand  for  some  hours,  filtered, 
washed  with  ammonium  carbonate  water,  obtaining  a  residue 
M'  on  the  filter  consisting  of  nearly  all  of  the  silicic  acid  plus 
a  little  iron  and  aluminum.  The  filtrate  and  washings  from 


THE  ANALYSIS  OF  FLUORSPAR  377 

Mf,  i.e.  Bf,  contain  the  last  traces  of  the  silica.  This  nitrate 
combined  with  B  contains  all  of  the  fluorine  as  sodium  fluoride 
and  the  remainder  of  the  silica  as  sodium  silicate.  This  silica 
is  removed  as  follows:  Evaporate  these  filtrates  to  dryness  in  a 
casserole;  take  up  with  as  little  water  as  possible;  add  a  few 
drops  of  an  alcoholic  solution  of  phenolphthaleine  and  then  add 
i  :  i  HC1  until  a  few  drops  of  this  acid  just  discharge  all  pink 
color.  The  solution  is  then  boiled  to  note  if  the  pink  color  may 
reappear,  and  if  it  should,  a  drop  or  two  more  of  the  acid  is  added 
to  just  remove  the  pink  and  so  on  until  no  pink  reappears  on 
heating.  The  solution  will  then  be  neutral  and  is  ready  for  the 
removal  of  the  last  traces  of  the  silicic  acid  by  means  of  a  satu- 
rated solution  of  zinc  oxide  in  ammonia,  prepared  as  follows: 
Dissolve  10  grams  of  zinc  oxide  in  50  c.c.  of  cone,  ammonia  and 
filter  off  the  undissolved  zinc  oxide.  Add  10  or  12  c.c.  of  this 
filtrate  to  the  neutralized  B  plus  B'  to  precipitate  the  silicious 
matter  still  remaining  therein,  as  zinc  silicate.  After  adding 
the  ammoniacal  zinc  solution,  boil  until  the  smell  of  ammonia  is 
gone,  and  then  filter  out  the  mixture  of  zinc  silicate  and  zinc 
oxide  and  wash  it  with  5  c.c.  of  the  ammoniacal  solution  of  zinc 
oxide  diluted  with  500  c.c.  of  water,  obtaining  filtrate  and  wash- 
ings C  which  contain  all  of  the  fluorine  as  sodium  fluoride  and 
free  of  silica.  The  silicic  acid  gotten  from  B  plus  Bf  as  zinc 
silicate  is  freed  from  zinc  by  dissolving  it  off  the  filter  with  nitric 
acid,  i. 20,  and  evaporating  the  filtrate  and  washings  so  obtained 
to  dryness.  The  dry  residue  is  taken  up  with  1.20  nitric  acid 
and  filtered  off,  after  dilution  with  water,  on  the  same  filter  from 
which  the  zinc  silicate  was  dissolved  with  nitric  acid.  The 
residue  on  this  filter  is  washed  thoroughly  and  burned  off 
with  M'. 

The  Calcium  Fluoride.  The  filtrate  C  is  heated  to  boiling 
and  the  fluorine  is  precipitated  from  it  while  boiling  by  means  of 
a  saturated  solution  of  calcium  carbonate.  Some  recommend 
the  addition  of  a  little  sodium  carbonate  before  adding  the  pre- 
cipitant, thus  causing  a  precipitation  of  some  calcium  carbonate 
along  with  the  calcium  fluoride  to  aid  in  the  subsequent  filtration. 


378  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  calcium  fluoride  is  filtered  and  washed  thoroughly  with 
water.  It  has  been  the  writer's  experience  that  it  requires  not 
less  than  50  washings  to  completely  wash  a  large  precipitate. 
The  CaF2  is  burnt  off  in  a  platinum  crucible  at  a  very  low  heat, 
just  smoking  off  the  paper,  and  then  at  low  red  to  remove  the 
carbon. 

The  ash  which  consists  of  a  mixture  of  oxide,  fluoride  and 
carbonate  of  calcium  is  dissolved  with  dilute  acetic  acid  (three 
parts  of  the  acetic  acid  diluted  with  i  part  of  water) ,  by  heating 
and  evaporation  to  dry  ness  on  the  water  bath.  The  calcium 
fluoride  remains  insoluble  and  the  calcium  carbonate  and  oxide 
are  dissolved.  After  the  evaporation  to  dryness,  50  c.c.  of  water 
are  added  to  the  dry  residue  and  heat  is  applied  for  about  a  half 
hour.  The  insoluble  calcium  fluoride  is  filtered  off  and  washed 
with  water,  dried,  ignited  at  a  low  heat  and  finally  at  redness 
until  the  CaF2  is  white,  when  it  is  cooled  and  weighed  and  cal- 
culated to  percentage  as  such.  As  a  check  on  the  purity  of  the 
CaF2  it  is  evaporated  to  dryness  with  5  c.c.  of  cone.  H2S04.  The 
excess  of  sulphuric  acid  is  driven  off  at  a  low  red  heat  and  the 
residue  is  weighed  as  calcium  sulphate,  1.7438  grams  of  which 
equal  i  gram  of  calcium  fluoride. 

Silica.  The  water-insoluble  residue  R'  is  smoked  off  in  a 
platinum  crucible  and  then  heated  at  redness  until  all  carbon 
from  the  paper  is  gone.  The  ash  which  contains  the  main 
calcium,  etc.,  is  transferred  to  a  porcelain  dish  and  boiled  for 
a  few  minutes  with  30  c.c.  of  i  :  i  HC1  until  all  but  per- 
haps a  little  silica  is  dissolved.  The  latter  is  filtered  off, 
washed,  designated  as  M"  and  burned  with  M' .  The  ash 
from  the  burning  .of  M'  plus  M"  contains  the  total  silica, 
that  is,  the  silica  that  was  added  plus  that  contained  in  the 
sample.  The  total  silica  is  then  evaporated  as  usual  with  an 
excess  of  HF1  plus  5  drops  of  cone.  H2SO4.  The  HF1  should 
be  added  very  cautiously,  and  in  small  installments,  to  prevent 
loss  by  spraying  during  the  formation  of  the  volatile  silicon 
fluoride.  The  silica  is  then  determined  by  the  loss  of  weight 
after  the  removal  of  the  excess  of  the  two  acids  as  in  steels.  Any 


THE  ANALYSIS   OF   FLUORSPAR  379 

residue  remaining  in  the  crucible  after  the  removal  of  the  silica 
may  contain  some  calcium,  iron,  etc.,  and  is  fused  with  a  little 
sodium  carbonate,  dissolved  in  HC1  and  added  to  the  nitrate 
from  M". 

Ca,  Mg,  Ba,  Fe  and  Al  are  now  all  in  solution  in  the  nitrate 
just  mentioned.  The  first  step  is  to  remove  any  barium  present 
by  adding  to  the  solution  2  c.c.  of  cone,  sulphuric  acid  diluted 
with  600  c.c.  of  water.  Any  precipitate  formed  by  the  addition 
of  the  very  dilute  sulphuric  acid  is  filtered  off,  ignited  and  weighed 
as  barium  sulphate.  The  filtrate  and  washings  from  the  barium 
sulphate  are  then  analyzed  for  Ca,  Mg,  iron  and  aluminum  as 
described  for  limestone,  beginning  at  the  point  where  these 
elements  are  all  in  solution  and  free  of  silica.  (See  page  357.) 

Blanks.  It  is  very  necessary  to  run  blanks  by  fusing  3  grams 
of  the  same  lot  of  precipitated  silica  as  used  in  the  decom- 
position of  the  spar  with  10  grams,  each,  of  the  sodium  and 
potassium  carbonates.  The  melt  is  dissolved  out  in  water  and 
then  put  through  all  of  the  operations  given  in  the  method.  The 
silica,  iron,  calcium,  magnesium  and  aluminum  so  found  are 
deducted  from  the  amounts  of  these  elements  found  in  the  analy- 
sis of  the  sample.  These  blank  analyses  should  be  made  in  dupli- 
cate, as  should  the  analysis  of  the  spar,  also. 

Lead.  Dissolve  0.9  and  i.o  gram  of  the  sample  in  a  mixture 
of  20  c.c.  of  cone.  HNO3  and  10  c.c.  of  cone.  HC1.  If  the  spar 
is  high  in  CaF2  it  will  dissolve  almost  completely  in  this  mixture. 
Heat  until  all  spraying  is  over  and  evaporate  to  moist  dryness; 
redissolve  in  20  c.c.  of  cone,  nitric  acid,  dilute,  filter,  wash  with 
dilute  nitric  acid,  and  evaporate  the  filtrate  and  washings  to 
10  c.c.  Add  75  c.c.  of  cone.  HC1  and  evaporate  to  15  c.c.  Dilute 
with  water  to  about  100  c.c.  Make  the  diluted  solution  just 
neutral  with  ammonia;  add  4  drops  of  HC1  and  pass  H2S  through 
the  hot  solution  until  the  black  precipitate  of  lead  sulphide 
settles  well.  Filter  off  the  lead  sulphide  and  wash  it  with  H2S 
water.  Pass  H2S  through  the  filtrate  and  washings  to  make 
certain  that  all  of  the  lead  has  been  precipitated.  The  lead 
sulphide  is  dissolved  in  50  c.c.  of  1.20  nitric  acid  and  its  solution 


380  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

is  evaporated  to  heavy  fumes  with  75  c.c.  of  i  :  3  sulphuric  acid, 
in  a  porcelain  dish.  Cool,  dissolve  as  far  as  possible  with  200 
c.c.  of  water  and  one-third  this  amount  of  alcohol.  Allow  the 
lead  sulphate  to  settle  for  several  hours  before  filtering;  filter 
off  the  lead  sulphate  and  wash  it  with  a  mixture  of  2  parts  of 
water  and  i  part  of  alcohol.  Burn  the  residue  at  a  very  low 
heat  in  a  porcelain  crucible  until  the  paper  is  all  gone.  Cool 
the  white  residue  and  moisten  it  with  a  drop  or  two  of  H2S04 
and  ignite  the  residue  again  at  a  dull  red  heat. 

The  weight  so  obtained  is  multiplied  by  0.6831  to  reduce  to 
the  metallic  basis.  If  the  sulphur  found  is  reported  as  such  then 
the  lead  can  be  conveniently  reported  as  metal.  The  lead  how- 
ever usually  is  present  as  the  sulphide. 

*  Sulphur.  The  author  uses  the  carbonate  and  nitre  fusion, 
melting  the  spar  with  20  grams  of  carbonate  of  soda  and  4  grams 
of  nitre.  The  analysis  is  then  finished  as  in  ferro-vanadium  high 
in  silicon  (see  page  17  near  the  bottom  of  the  page).  There  is 
no  reason  why  the  sulphur  could  not  be  obtained  by  fusing  the 
mineral  in  15  grams  of  peroxide  and  then  dissolving  out  the 
melt  in  water.  The  water  solution  could  be  acidulated  with  a 
considerable  excess  of  HC1  and  the  analysis  finished  as  in  the 
carbonate  and  nitre  fusion. 

In  either  method  blanks  should  be  run  through  all  the  opera- 
tions and  deducted. 

Carbon  Dioxide.  Ignite  i  gram  of  the  sample  in  the  electric 
combustion  furnace  in  a  stream  of  oxygen  for  one  hour,  as  in  the 
determination  of  carbon  in  steel.  The  carbon  dioxide  is  usually 
combined  with  calcium,  as  carbonate,  in  the  mineral. 

APPROXIMATE  METHOD. 

The  usual  approximate  method  is  to  attack  the  spar  with 
acetic  acid.  The  author  proceeds  as  follows  (he  regards  the 
approximate  method  accurate  enough  for  all  technical  purposes) : 
Moisten  the  finely  ground  spar  to  a  thin  paste  with  water,  add 
20  c.c.  of  glacial  acetic  acid  and  evaporate  to  dryness  on  the 
water  bath  in  a  porcelain  dish.  To  the  dry  residue  add  50  c.c. 


THE  ANALYSIS  OF  FLUORSPAR  381 

of  water;  stir,  boil  a  few  minutes;  add  ashless  paper  pulp;  mix 
again,  filter  and  wash  with  hot  water,  obtaining  residue  R  on 
the  filter  and  filtrate  and  washings  F.  The  residue  R  con- 
tains all  of  the  CaF2,  silica  and  the  main  portion  of  the  iron, 
aluminum  and  lead.  Barium  if  present  as  sulphate  would  be 
mainly  in  R. 

The  filtrate  and  washings  from  R  contain  calcium,  mag- 
nesium and  some  of  the  iron  and  aluminum,  and  are  analyzed 
for  these  elements  as  in  limestone  (see  page  357).  If  lead  is 
present  some  of  it  will  also  be  in  this  filtrate  and  should  be  first 
removed  by  H2S  precipitation  of  the  hot,  faintly  acid  solution. 
The  lead  sulphide  is  washed  with  H2S  water  and  the  filtrate  and 
washings  are  evaporated  low  to  remove  the  excess  of  H2S,  add- 
ing some  potassium  chlorate  to  -oxidize  the  iron,  at  the  beginning 
of  the  evaporation.  The  amount  of  lead  found  at  this  point  is 
only  a  small  portion  of  the  total  amount  of  the  lead  present;  at 
least,  this  is  the  case  in  the  samples  containing  lead  as  galena. 

Silica  and  Calcium  Fluoride.  The  residue  R  is  ignited  at 
a  low  red  heat  in  a  weighed  platinum  crucible,  cooled  and 
weighed.  20  c.c.  of  c.p.  HF1  are  added  to  R  after  the  weigh- 
ing. Evaporation  to  dryness  removes  the  silica.  The  remain- 
der in  the  crucible  is  then  heated  to  lowest  redness,  cooled, 
weighed  again,  and  the  loss  of  weight  due  to  the- evaporation 
and  ignition  is  calculated  as  silica.  3  c.c.  of  cone.  H2SO4  are 
dropped  into  the  crucible  and  the  contents  of  the  latter  are 
taken  to  dryness;  ignited  at  a  low  red  heat,  cooled  and  weighed 
as  calcium  sulphate  (CaSCX).  The  calcium  sulphate  so  found 
is  calculated  to  calcium  fluoride  after  deducting  from  it  any 
Ba,  Pb,  Fe  and  Al  found  as  given  below. 

Add  15  c.c.  of  cone.  HC1  to  the  weighed  calcium  sulphate  and 
boil  it  until  the  sulphate  either  dissolves  to  a  clear  solution  after 
20  minutes  slow  boiling,  or  there  remains  some  white  insoluble 
residue  which  would  indicate  the  presence  of  barium  sulphate. 
If  such  a  residue  be  found,  then  dilute  the  solution  to  200  c.c. 
and  let  it  stand  for  several  hours  to  permit  the  barium  sulphate 
to  settle.  Filter  it  out;  wash  it  with  water;  ignite,  cool,  weigh, 


382  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

and  deduct  it  from  the  weight  of  the  calcium  sulphate.  The 
nitrate  and  washings  from  the  barium  sulphate  are  diluted  to 
400  c.c.  and  H^S  is  passed  for  an  hour  and  the  solution  is  then 
permitted  to  stand  for  several  hours  to  give  the  precipitate  of 
PbS  time  to  separate  out.  If  there  be  sulphide  of  lead  in  the 
spar  (usually  in  the  form  of  galena),  then  some  of  it  will  have 
been  counted  as  calcium  sulphate.  The  lead  sulphide  is  burned 
at  a  very  low  red  heat  in  a  porcelain  crucible,  moistened  with  a 
few  drops  of  cone,  sulphuric  acid  and  the  latter  is  evaporated. 
The  residue  is  burned  at  a  low  red  heat,  weighed  and  the  weight 
is  then  deducted  from  that  of  the  calcium  sulphate.  The 
nitrate  and  washings  from  the  lead  sulphide  are  evaporated  to 
dryness  with  a  gram  or  two  of  potassium  chlorate  and  analyzed 
for  any  small  amounts  of  iron  and  aluminum  that  may  be  pres- 
ent in  this  part  of  the  analysis;  that  is,  the  small  residue  in  the 
evaporating  dish  is  dissolved  in  10  c.c.  of  HC1,  precipitated  with 
a  slight  excess  of  ammonia,  the  small  precipitate  of  iron  and 
aluminum  hydroxides  are  filtered  out,  washed,  weighed  and  the 
weight  also  deducted  from  the  weight  of  main  calcium  sulphate. 
The  main  calcium  sulphate  as  stated,  after  these  deductions,  is 
then  calculated  to  the  total  calcium  fluoride.  These  small  por- 
tions of  the  Fe  and  Al  are  also  added  to  the  main  oxides  of  iron 
and  aluminum  found  in  F.  The  main  filtrate  F  contains  all  of  the 
calcium  and  magnesium  not  existing  in  the  mineral  as  fluorides; 
also  the  remainder  of  the  lead  if  any  is  present  and  the  main 
portion  of  the  iron  and  aluminum.  The  lead  is  removed  first, 
after  acidulating  F  with  a  slight  excess  of  HC1  to  prevent  the 
coprecipitation  of  any  iron,  by  means  of  hydrogen  sulphide. 
The  filtrate  and  washings  from  the  lead  sulphide  are  evaporated 
to  dryness  with  an  excess  of  at  least  20  c.c.  of  cone.  HC1  and  i 
gram  of  chlorate.  The  dry  residue  is  then  taken  up  with  10  c.c. 
of  i  :  i  HC1  and  the  iron,  aluminum,  calcium  and  magnesium 
in  the  solution  are  determined  as  in  limestone.  As  stated,  the 
lead,  iron  and  aluminum  found  here  are  added  to  any  portions 
of  these  elements  found  in  the  filtrate  from  the  hydrochloric 
solution  of  the  calcium  sulphate. 


THE  ANALYSIS  OF  FLUORSPAR  383 

CALCULATIONS. 

In  the  exact  method,  the  calcium  required  in  the  calcium  flu- 
oride found  is  deducted  from  the  total  calcium  found.  Any 
calcium  remaining  is  usually  calculated  to  calcium  carbonate. 
The  author  prefers  for  the  sake  of  simplicity  to  calculate  to 
calcium  oxide  the  calcium  found  in  excess  of  that  necessary  to 
produce  the  calcium  fluoride;  and  report  the  carbon  dioxide 
found  as  such  instead  attempting  to  distribute  it  as  carbonate. 
In  the  same  way  the  sulphur  found  is  reported  as  such  instead 
of  entering  into  a  tedious  computation  for  the  purpose  of  cal- 
culating a  part  of  it  to  lead  sulphide  and  any  remaining  sulphur 
to  sulphide  of  iron.  Similarly  the  oxides  of  iron  and  aluminum 
obtained  are  reported  as  oxides.  For  commercial  and  technical 
purposes  this  seems  the  logical  procedure,  and  entirely  answers 
purposes  of  the  iron  and  steel  metallurgist.  In  harmony  with 
the  reporting  of  the  sulphur  as  such,  the  lead  found  is  recorded 
as  metal. 

CALCULATION  OF  THE  CALCIUM  EXISTING  AS  CAO  BY  THE 
EXACT  METHOD. 

Suppose  that  83.46  per  cent  of  CaF2  were  found.  Then  in 
one  gram  of  the  sample  there  would  be  0.8346  gram  of  calcium 
fluoride.  Further,  in  one  gram  of  this  sample  there  was  found 
a  total  of  0.6956  gram  of  calcium  oxide  in  the  filtrate  from 
M" ,  page  378;  then  as  calcium  fluoride  is  converted  to  its 
equivalent  weight  of  calcium  oxide  by  the  factor  0.7182  we 
have  0.8346  multiplied  by  0.7182  or  0.5994  gram  of  calcium 
oxide  coming  from  the  calcium  in  the  calcium  fluoride.  This 
'is  deducted  from  the  total  calcium  oxide;  0.6956  minus  0.5994, 
or  0.0962  gram  of  calcium  oxide  to  be  reported  as  such,  being 
9.62  per  cent. 

CALCULATION  OF  CaS04  TO  CaF2  IN  THE  APPROXIMATE 

METHOD. 

The  calcium  sulphate  found  is  multiplied  by  the  factor  0.5735 
to  obtain  the  equivalent  weight  of  calcium  fluoride. 


384  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

SOME  ANALYSES  OF  FLUORSPAR. 


Sample  of  Fairview  Gravel. 

Calcium  fluoride              

Approximate  Method. 
Per  Cent. 

Exact  Method. 
Per  Cent. 

83.70 
2.92 
3-16 
9.40 
0.016 

83.46 
3-20 
3-20 
9.61 
0.016 

Silica                                 

Oxides  of  iron  and  aluminum 

Calcium  oxide 

Sulphur                                              .  . 

Sample  of  Fluorspar  Gravel  Containing  Sulphide  of  Lead. 


Approximate  Method. 
Per  Cent. 

Exact  Method. 
Per  Cent. 

Calcium  fluoride 

84   24 

84   ^6 

Silica 

c   44 

c  .  79 

Oxides  of  iron  and  aluminum 

1  .  32 

1  .41 

Calcium  oxide                       

1.83 

1.90 

Carbon  dioxide    .              

2.  2O 

2.  2O 

Sulphur        

0.92 

0.92 

Metallic  lead 

2    OO 

2  .OO 

Moisture  

O-3S 

O-35 

Selected  Sample  by  the  Approximate  Method. 


Calcium  fluoride  
Silica 

Per  Cent. 
97.58 
o.  20 

Oxides  of  iron,  etc  
Oxide  of  calcium  

Per  Cent. 
0.77 
0.62 

CHAPTER  XIX. 

PART  I. 
THE  TESTING  OF  LUBRICATING  OILS. 

As  the  steel  works'  chemist  is  frequently  required  to  report 
on  the  lubricants  used  about  the  plant,  a  brief  outline  of  the 
more  important  tests  may  save  the  busy  reader  of  this  book 
much  delving  into  the  vast  amount  of  literature  written  on 
this  subject.  The  tests  about  to  be  described  constitute  all 
that  the  mechanical  engineering  department  of  a  large  works 
usually  cares  to  know,  or  asks  for.  If  the  reader  wishes  to  in- 
form himself  further,  he  can  consult  the  writings  of  Lewkowitch, 
Benedict,  Gill  and  others. 

SAPONIFICATION  NUMBER. 

This  test  is  a  direct  index  of  the  proportion  of  animal  matter 
in  the  lubricant  for  the  reason  that  mineral  oil  (usually  present 
in  most  of  the  oils  used  for  lubricating)  has  no  saponification 
value.  The  saponification  number  simply  means  that  one  gram 
of  the  sample  tested  requires  that  many  milligrams  of  potassium 
hydroxide  to  combine  with  (saponify)  the  fatty  acids  present  in 
it.  The  test  is  also  known  as  the  Koettstorfer's  value. 

METHOD. 

Weigh  i  to  2  grams  of  the  oil  or  lubricant  into  a  250  c.c.  coni- 
cal flask.  Place  also  in  the  flask  25  c.c.  of  half  normal  potas- 
sium hydroxide.  Insert  a  stopper  carrying  a  return  condenser 
firmly  in  the  neck  of  the  flask.  Turn  a  current  of  water  into 
the  condenser  and  start  to  heat  the  flask  on  a  water  bath.  (See 
photo  No.  27.)  Some  operators  add  20  c.c.  of  ether  to  the  con- 
tents of  the  flask  before  putting  in  the  condenser.  Heat  the  flask 
on  the  water  bath  for  one  hour.  Then  shut  off  the  heat,  turn  off 
the  water,  cool,  add  several  drops  of  phenolphthaleine  indicator 

385 


386  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

and  drop  in  from  a  burette  half-normal  HC1  until  the  pinkish 
color  or  shade  given  to  the  solution  by  the  indicator  just  disap- 
pears. The  number  of  c.c.  of  N/2  KOH  added,  less  the  number 
of  c.c.  of  HC1  required  to  discharge  the  pinkish  color  produced 
by  the  KOH,  multiplied  by  the  factor  28.05  (x  c-c-  of  N/2  KOH 
contains  28.05  nigs,  of  KOH)  and  divided  by  the  weight  of  the 


PHOTO  27. 

oil  taken  gives  the  saponification  number  of  the  sample.  In 
weighing  the  oil  place  the  tared  flask  on  the  balance  pan  and 
drop  in  some  of  the  sample  from  a  pipette  until  about  the 
desired  weight  has  been  put  in  the  flask.  Then  weigh  the  oil 
exactly. 

When  titrating  the  oil  with  N/2  HC1  use  alcohol  to  wash 
down  the  sides  of  the  flask,  as  water  is  liable  to  cloud  the  solu- 
tion. To  check  the  operations  place  25  c.c.  of  the  N/2  KOH 
in  the  cone  flask  together  with  the  20  c.c.  of  ether.  Connect 
the  condenser  and  heat  the  flask  for  one  hour  in  the  water  bath, 
cool  and  titrate  with  the  N/2  HC1.  Any  KOH  that  may  have 


THE  TESTING  OF  LUBRICATING  OILS  387 

been  so  used  is  deducted  from  the  apparent  amount  used  by 
the  sample,  before  calculating  the  saponification  number  as 
given  above. 

A  convenient  standard  for  checking  the  operator's  work  is 
the  purest  rapeseed  oil.  A  very  pure  sample  obtained  by  the 
writer  gave  a  saponification  value  of  185.  A  German  rape  oil 
known  as  double  refined  was  found  to  be  182  in  saponification. 
Pure  lard  oil  is  given  as  195.  These  pure  oil  standards  should 
be  kept  in  a  cool  dark  cupboard,  in  sealed  bottles,  when  not 
in  use. 

THE  PREPARATION  OF  HALF-NORMAL  (N/2)  HC1  AND 
HALF-NORMAL  KOH. 

A  normal  solution  is  usually  defined  as  the  hydrogen  gram 
equivalent  of  the  active  substance  dissolved  in  a  liter  volume. 
The  author  would  like  to  offer  the  following  definition  which 
may  seem  long  drawn  out  but  more  explanatory: 

A  normal  solution  is  the  gram  molecular  weight  of  the  react- 
ing substance  dissolved  in  a  liter  volume,  or  that  fraction  of  its 
gram  molecular  weight  dissolved  in  a  liter  volume  which  is  the 
equivalent  of  the  gram  atomic  weight  of  hydrogen.  The  re- 
quired fraction  of  the  gram  molecular  weight  may  be  different 
for  the  same  compound,  depending  on  the  nature  of  the  reac- 
tion for  which  the  normal  solution  is  to  be  used. 

The  first  requisite  is  then  to  write  the  equation  and  from  it 
decide  whether  the  full  molecular  weight  in  grams  or  only  a 
fraction  of  it  is  needed  to  meet  the  conditions  of  normal  solution. 
Suppose  the  normal  solution  of  permanganate  of  potassium  is 
desired  for  the  oxidation  of  ferrous  sulphate,  according  to  the 
equation : 

(A)  10  FeS04  +  2  KMn04  +  8  H2SO4  =  5  Fe2(S04)3  +  K2S04 

+  2  MnS04  +  8  H2O, 

or 

(B)  10  FeO  •  S03  +  K2O2  -  2  MnO3  +  8  H2O  -  SQ3  =  5  Fe203  (S03)3 

+  K2O  •  SO3  +  2  MnO  •  S03  +  8  H2O. 


388  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

By  equation  (B)  we  see  how  the  oxidation  expressed  by  (A) 
takes  place:  The  ferrous  oxide  united  to  the  sulphuric  radical 
and  containing  10  atoms  of  oxygen  becomes  ferric  oxide,  still 
united  to  the  sulphuric  radical,  and  gains  5  atoms  of  oxygen. 
This  gain  comes  from  the  permanganate  as  by  equation  (B)  the 
potassium  peroxide  part  of  the  permanganate  loses  i  atom  of 
its  oxygen  to  the  ferrous  sulphate,  becoming  potassium  sulphate; 
and  the  two  parts  of  manganic  trioxide  give  up  four  atoms  of 
oxygen  to  the  ferrous  sulphate,  and  become  2  molecules  of  man- 
ganous  sulphate.  Hence  we  .have  permanganate  equivalent  to 
5  atoms  of  divalent  oxygen  or  10  atoms  of  monavalent  hydro- 
gen ;  therefore  2  molecules  of  the  permanganate  being  equivalent 
to  10  atoms  of  hydrogen  then  2/ioths  or  i/5th  of  a  gram  molecule 
of  the  KMnO4  will  be  the  equivalent  of  the  gram  atom  of  hydro- 
gen. This  makes  it  necessary  to  weigh  i/5th  of  158.03  or  31.6 
grams  of  the  KMnO4,  dissolving  the  same  in  a  liter  volume. 

A  normal  solution  of  the  ferrous  sulphate:  It  has  been  seen 
that  the  sulphate  of  iron  has  taken  up  5  atoms  of  oxygen  which 
are  equivalent  to  10  atoms  of  hydrogen,  hence,  since  10  molecules 
of  the  ferrous  sulphate  are  equivalent  to  10  atoms  of  hydrogen, 
then  i  molecule  t  of  trie  sulphate  is  equivalent  to  i  atom  of  hydro- 
gen. It  will  be  fulfilling  the  definition  if  2 78  grams  of  FeS04,7  H2O 
are  dissolved  in  a  liter  volume,  or  the  entire  gram  molecule. 

An  example  of  a  normal  solution  for  a  precipitation  reaction 
is  afforded  by  the  following:  H2S04  +  BaCl2  =  BaSO4  + 
2  HC1.  In  this  equation  the  active  sulphuric  acid  molecule 
precipitates  the  divalent  barium  atom  which  is  equivalent  to  2 
atoms  of  the  monavalent  hydrogen  atom,  therefore  \  the  gram- 
molecular  weight  of  the  sulphuric  acid,  or  49.04  grams  of  the 
ico  per  cent  acid  or  its  equivalent  in  a  dilution,  in  a  liter  volume 
constitutes  its  normal  solution. 

(C)  This  brings  one  to  the  neutralization  normal,  or  half- 
normal  solution:  HC1  +  KOH  =  KC1  +  H2O.  In  this  reac- 
tion whether  it  is  desired  to  consider  the  normal  solution  for  the 
potassium  hydroxide  or  the  hydrochloric  acid  it  is  an  example  of 
one  molecule  reacting  with  a  monavalent  atom.  In  either  case 


THE  TESTING  OF  LUBRICATING  OILS  389 

the  entire  gram  molecule  would  be  required  in  the  liter  volume 
or  one-half  this  amount  for  the  half-normal  solution,  also  in  a 
liter  volume.  This  would  be  36.47  grams  of  the  HC1  and  56.11 
grams  of  the  KOH  in  a  liter  volume  for  the  normal  solution,  or 
18.23  grams  of  HC1  and  28.05  grams  of  KOH  dissolved  in  a  liter 
volume  for  the  half-normal  solution  (N/2)  of  these  salts. 

Half-normal  HCL 

As  the  hydrochloric  solution  will  remain  constant,  7  liters 
are  prepared  as  follows:  350  c.c.  of  about  1.20  specific  gravity 
acid  are  diluted  to  7000  c.c.  with  water  and  well  mixed.  The 
acidity  is  then  tested  against  pure  sodium  carbonate  prepared 
from  c.p.  sodium  oxalate  which  can  be  obtained  to  the  best 
advantage  from  the  U.  S.  Bureau  of  Standards. 

Weigh  i  gram  of  the  standard  oxalate  into  a  platinum  cru- 
cible and  gently  ignite  until  it  is  charred  and  then  raise  the 
heat  until  it  is  pure  white  but  do  not  heat  it  above  redness. 
Dissolve  the  sodium  carbonate  thus  formed  in  a  little  water 
and  transfer  it  with  great  care  to  a  250  c.c.  cone  flask.  Add  i 
or  2  drops  of  methyl  orange  solution  and  titrate  it  with  some 
of  the  above  HC1  solution  until  one  drop  of  the  acid  just  turns 
the  fluid  in  the  cone  flask  pink.  The  reaction  is  as  follows: 

Na^COs  +  2  HC1  =  2  NaCl  +  H20  +  C02.  (2) 

The  sodium  oxalate  on  ignition  is  decomposed  to  sodium  car- 
bonate in  the  manner  shown  by  the  equation, 

Na2C204  +  O  =  NaoCOs  +  C02.  (i) 

By  (i)  one  molecule  of  sodium  oxalate  yields  i  molecule  of 
sodium  carbonate  and  by  (2)  we  see  that  i  molecule  of  sodium 
carbonate  is  also  equivalent  to  2  molecules  of  hydrochloric 
acid.  Or  in  terms  of  equivalent  weights,  134  parts  of  sodium 
oxalate  yield  106  parts  of  sodium  carbonate,  which  require 
72.94  parts  of  HC1  (2  HC1)  for  neutralization,  i  gram  of 
sodium  oxalate  will  give  io6/i34ths  of  a  gram  of  sodium 


390  CHEMICAL  ANALYSIS  OF   SPECIAL  STEELS 

carbonate,  or  0.791  gram.  Suppose  that  the  trial  titration  of 
7  liters  of  HC1  showed  that  0.791  gram  of  sodium  carbonate 
required  25.0  c.c.  of  this  HC1  to  give  a  pink  with  the  methyl 
orange.  By  (2)  we  have  seen  that  72.94  parts  by  weight  of 
HC1  unite  with  106  parts  of  sodium  carbonate  or  1.4532  grams 
of  NaaCOa  equal  i  gram  of  HC1.  N/2  HC1  according  to  (C) 
contains  18.23  grams  of  HC1  to  the  liter,  therefore  i  c.c.  of 
N/2  HC1  equals  18.23  X  1.4532  -i-  1000  grams  of  sodium  car- 
bonate, or  0.02650  gram  of  Na2CO3.  As  an  average  of  several 
titrations  it  was  found  that  25  c.c.  of  the  solution  of  HC1  being 
tested  neutralized  0.791  gram  of  Na^COs,  hence  i  c.c.  of  this 
acid  equals  0.791  gram  -i-  25,  or  0.03164  gram  of  NasCOs.  As 
i  c.c.  of  N/2  HC1  should  equal  0.02650  gram  of  Na2CO3  then 
i  c.c.  of  the  acid  being  tested  should  be  diluted  in  volume  as 
many  times  as  0.0265  *s  contained  in  0.03164,  or  1.194  times. 
Suppose  after  making  the  trial  titrations  there  remains  exactly 
6800  c.c.  of  the  HC1,  then  this  solution  should  be  diluted  to 
6800  X  1.194  c.c.,  or  to  8119  c.c.,  when  it  should  be  an  exact 
N/2  normal  solution. 

In  general  divide  any  number  of  c.c.  of  the  acid  being  stand- 
ardized into  the  amount  of  sodium  carbonate  that  it  will  ex- 
actly neutralize;  divide  the  result  by  0.02650  and  then  multiply 
this  last  quotient  by  the  exact  number  of  c.c.  of  the  acid  remain- 
ing. This  will  give  the  volume  to  which  the  remaining  acid 
must  be  diluted  to  make  it  of  N/2  strength. 

THE  PREPARATION  OF  N/2  KOH. 

Weigh  about  40  grams  of  KOH,  marked  purified  by  alcohol, 
into  a  glass  stoppered  bottle  and  dissolve  it  in  a  liter  of  ethyl 
alcohol  that  has  been  distilled  with  some  KOH. 

This  distillation  can  be  accomplished  by  placing  the  alcohol 
and  KOH  in  a  boiling  flask,  in  boiling  water  and  connecting 
the  same  with  a  Bunsen  condenser.  The  distillate  is  then  used 
as  above.  In  the  alcoholic  solution  a  gram  or  two  of  barium 
hydroxide  are  also  placed  to  remove  any  carbonate  present  in 


THE  TESTING  OF  LUBRICATING  OILS  391 

the  KOH  solution.  It  is  then  allowed  to  settle  for  twelve  hours, 
when  the  clear  liquid  is  siphoned  off,  leaving  all  of  the  cloudy 
portion  behind.  This  clear  portion  is  diluted  to  one  liter  and 
well  mixed  in  a  glass  stoppered  volumetric  flask.  The  redis- 
tilled alcohol  is  used  for  this  dilution  also.  Exactly  50  c.c.  of 
this  KOH  are  withdrawn  from  the  1000  c.c.,  and  25  c.c.  of  it  are 
titrated  with  the  N/2  HCL  Suppose  it  is  found  that  28.7  c.c.  of 
the  N/2  HC1  are  required  to  just  turn  the  25  c.c.  of  the  KOH 
pink;  then  i  c.c.  of  the  KOH  equals  28.7  -f-  25,  or  1.148  c.c.  of 
the  HCL  Hence  the  950  c.c.  of  the  KOH  that  remain  must  be 
diluted  to  950  X  1.148,  or  1090  c.c.  to  make  them  the  equivalent 
of  the  N/2  HC1  and  therefore  an  N/2  KOH  solution.  This  dilu- 
tion is  made  as  in  the  others  with  the  alcohol  that  has  been 
distilled  in  the  presence  of  KOH. 

CALCULATIONS. 

In  actual  work  the  N/2  KOH  does  not  remain  for  any  length 
of  time  exactly  of  N/2  strength  so  it  is  more  convenient  to 
determine  its  exact  relation  to  the  N/2  HC1,  which  latter  acid 
should  remain  unchanged.  Suppose  it  is  found  as  a  result 
of  the  mean  of  several  titrations  of  the  HC1  against  the  KHO 
that  the  29.2  c.c.  N/2  HC1  equal  30  c.c.  of  the  KOH.  Since 
i  c.c.  of  N/2  HC1  reacts  with  exactly  28.05  mSs-  °f  KOH, 
i  c.c.  of  the  KOH  solution  being  tested  is  equivalent  to  28.05  X 
29.2  -=-  30  c.c.,  or  27.30  mgs.  of  KOH,  which  value  can  then  be 
used  at  that  time,  instead  of  the  factor  28.05  which  can  be  used 
only  when  the  KOH  is  exactly  normal. 

FLASH  AND  FIRE  TESTS. 

The  writer  uses  the  open  fire  tester  of  Tagliabue. 

Place  a  bed  of  chip  graphite  in  the  bottom  of  the  tester.  Fill 
the  reservoir  with  the  oil  to  within  J  inch  of  the  top  and  raise  the 
temperature  at  the  rate  of  15  degrees  per  minute;  try  for  a  small 
flash  of  flame  across  the  surface  of  the  oil  every  7  degrees.  After 
getting  the  flash  make  note  of  the  temperature  and  continue 


3Q2  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

to  raise  the  same  until  the  oil  takes  fire  and  note  this  tempera- 
ture which  is  the  ftie  test.  For  an  igniter  use  a  small  glass  jet 
in  a  rubber  hose  connection  so  that  the  flame  coming  from  the 
jet  is  not  more  than  one-eighth  of  an  inch  long.  In  using  this 
small  igniting  flame  draw  it  across  the  diameter  of  the  surface 
of  the  oil  and  keep  the  little  flame  on  a  level  with  the  top  of  the 
tester,  making  sure  that  the  jet  does  not  touch  the  oil  at  any 
time.  Keep  the  tester  surrounded  with  a  sheet  iron  cylinder 
during  the  testing  to  protect  it  from  draughts.  This  test  should 
be  always  carried  out  under  exactly  the  same  conditions  or  the 
results  will  be  discordant.  When  the  burning  test  has  been 
completed  smother  the  flame  at  once  with  the  cover  that  goes 
with  the  instrument  as  this  serves  to  put  out  the  flame  and 
makes  the  tester  easier  to  clean  for  the  next  sample. 

Consult  Technical  paper  No.  49,  Dept.  of  Interior,  Bureau 
of  Mines,  by  Allen  and  Crossfield,  1913,  on  the  Flash  Point  of 
Oils. 

COLD  TEST. 

Fill  a  4-ounce  wide  neck  glass  stoppered  bottle  about  half 
full  of  the  oil  and  place  it  in  a  freezing  mixture  consisting  of 
2  parts  of  ice  and  i  part  of  salt,  which  can  be  kept  in  a  small 
can  wrapped  with  asbestos.  After  the  oil  is  solid,  let  it  stand 
in  the  mixture  for  about  an  hour.  Then  take  out  the  bottle 
and  place  a  thermometer  in  it  and  stir  with  the  thermometer 
until  the  oil  will  just  flow  from  one  end  of  the  bottle  to  the 
other.  The  cold  test  is  that  temperature  at  which  the  oil  will 
just  flow. 

TEST  FOR  FREE  ACID. 

This  test  is  usually  reported  in  grams  of  free  oleic  acid  and 
N/6  KOH  is  used  for  the  purpose,  i  c.c.  of  which  is  equal  to 
0.047  gram  of  free  oleic  acid.  Weigh  8  to  10  grams  of  the  oil, 
accurately,  into  a  250  c.c.  cone  flask.  Add  100  c.c.  of  the  redis- 
tilled alcohol  prepared  as  given  under  Saponification.  Put  the 
flask  in  a  water  bath  and  bring  the  contents  quickly  to  just  60°  C. 
Then  take  the  flask  off  the  bath  at  once  and  titrate  with  the 


THE  TESTING  OF  LUBRICATING  OILS  393 

N/6  KOH  until  the  first  pink  color  just  spreads  through  the  test. 
Do  not  carry  the  titration  any  further  or  the  result  will  be  too 
high  due  to  a  certain  amount  of  saponification  taking  place. 
The  number  of  c.c.  required  to  produce  this  first  pink,  multiplied 
by  0.047  and  divided  by  the  weight  taken  gives  the  amount  of 
free  oleic  acid  per  gram  which  is  then  reported  in  percentage. 

The  alcohol  used  in  these  tests  can  be  recovered  by  distilling 
off  the  same  after  the  tests  are  completed.  Add  some  quick- 
lime to  the  fluid  before  distilling  off  the  alcohol  to  remove  any 
water. 

VISCOSITY. 

Any  of  the  vicosimeters  on  the  market  can  be  used  for  this 
test.  The  writer  also  uses  the  Tagliabue  instrument  for  this 
work.  Full  directions  go  with  these  instruments  so  that  but 
a  brief  hint  or  two  is  all  that  is  necessary.  For  testing  the  oil 
at  70  degrees  attach  the  nipple  marked  70  degrees  to  the  outlet 
and  be  sure  that  the  oil  has  no  dirt  in  it.  If  the  room  temperature 
is  above  70  degrees  pour  90  c.c.  of  the  oil  into  the  container  and 
just  as  soon  as  the  oil  reaches  the  required  temperature  allow 
70  c.c.  to  pass  through  the  nipple,  timing  its  flow  in  seconds 
with  a  stop  watch.  The  number  of  seconds  required  multi- 
plied by  two  gives  the  viscosity. 

To  test  oil  at  212  degrees  water  is  brought  to  that  temper- 
ature in  the  boiler  of  the  viscosimeter,  and  the  steam  coming 
from  the  water  passes  through  the  steam  jacket  of  the  instru- 
ment which  surrounds  the  oil  container.  80  c.c.  of  the  sample 
which  has  already  been  heated  to  22  degrees  or  more  are  now 
placed  in  the  oil  container,  and  when  the  212  degrees  are  reached 
in  the  oil,  as  shown  by  the  thermometer  that  goes  with  the 
instrument,  60  c.c.  of  the  oil  are  withdrawn  through  the  nipple 
marked  212  degrees  and  the  time  of  its  flow  is  recorded  in 
seconds  with  the  stop  watch.  The  seconds  required  multiplied 
by  two  give  the  viscosity. 

The  Engler  viscosimeter  refers  all  viscosity  values  to  the 
same  figures  obtained  by  passing  distilled  water  through  his 
instrument.  The  figures  obtained  on  the  oil  tested  are  divided 


394 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


by  those  gotten  from  water  in  the  same  way.     This  gives  what 
he  terms  the  specific  viscosity. 

The  viscosimeter  should  be  cleaned  with  ether  after  each 
test  to  prevent  any  gummy  coating  forming  on  the  walls  of  the 
nipples  which  would  impair  the  accuracy  of  the  instrument. 
The  viscosity  of  water  for  this  instrument  used  in  this  laboratory 
was  found  to  be  40  at  70  degrees  and  75  at  212  degrees. 

SPECIFIC  GRAVITY. 

For  the  determination  of  specific  gravity  the  Eichorn  pic- 
nometer  is  used.  Cool  the  oil  to  60°  F.  and  fill  the  little  bulb 
slowly  with  the  oil  so  that  no  air  bubbles  enter  with  the  oil,  as 
the  presence  of  air  in  the  reservoir  renders  the  result  entirely 
inaccurate.  Hold  the  picnometer  at  about  a  70  degree  angle 
when  filling  it  so  that  the  bubbles  may  be  worked  out  to  a  better 
advantage.  When  the  bulb  is  entirely  full  of  the  oil,  and  free 
of  air,  stopper  it,  wipe  it  free  of  oil,  place  it  in  a  cylinder  of  water 
which  is  at  60°  F.  and  read  the  specific  gravity  from  the  gradua- 
tion of  the  instrument  that  is  tangent  to  the  meniscus  curve 
of  the  surface  of  the  water. 

RESULTS  OF  SOME  OIL  TESTS. 

Cylinder  Oil. 


Acid 
Test. 

Flash. 

Fire. 

Viscos- 
ity, 

212°  F. 

Sp. 
Grav. 

Sap. 
Val. 

Cold 
Test. 

2/7/12. 

United 
Cylinder  oil 

Per  Cent 
0.168 
O    27O 

Degrees 

546 
ccc; 

Degrees 
628 
630 

153 
184 

0.895 
0.89 

20-53 
22  .6l 

Degrees 
40 
37 

Capitol. 

o.  232 

566 

646 

197 

0.898 

22.24 

36 

Dark  crescent  

3/18/12. 

Capitol 

O.126 

505 

558 

161 

0.914 

18.30 

39 

8/I3/I2. 

Special  600  
High  standard  

o  .  00496 

O.OO2I5 

492 
508 

526 
552 

139 
185 

0.910 
0.918 

22.45 
17.84 

26 
3° 

No   i  Oil  City  Oil. 

O   OOIO 

^90 

642 

189 

0.890 

16.93 

37 

No.  2  Oil  City  Oil  

0.00108 
0.00223 

555 
505 

622 
57° 

162 

148 

0.884 
0.880 

16.45 
21  .25 

32 
42 

0.003 

462 

522 

125 

0.882 

8.98 

44 

Capitol  cylinder  oil  .... 

O.OO2 

55i 

618 

178 

0.893 

6.41 

4i 

THE  TESTING  OF  LUBRICATING  OILS 

Lubricating  Oil. 


395 


Acid 
Test. 

Flash. 

Fire. 

Viscos- 
ity, 

212°  F. 

Sp. 
Grav. 

Sapon. 
Value. 

Cold 
Test. 

Brook's  

o  144 

558 

628 

1  60 

0  802 

17   60 

3C 

Young's  

o.  113 

^30 

588 

134 

0.8o< 

3O.  24 

46 

Voegley  

0.258 

546 

624 

185 

0.896 

21.78 

40 

W.  V.  Lub. 

O    I  3Q 

3^7 

2QQ 

IO2 

o  884 

8  020 

JC 

MISCELLANEOUS   OILS. 


Acid 
Test. 

Flash. 

Fire. 

Viscos- 
ity, 

212°  F. 

Sp. 
Grav. 
60°  F. 

Cold 
Test. 

Sap. 
Val. 

8/22/12. 

Roll  oil.. 

o  016 

4O4 

4"?0 

187 

o  870 

17°  F 

2O    1  2 

Tempering  oil.  .  .    . 

o  0038 

488 

rtT2 

142 

o  860 

31  6°F. 

2    82 

Torch  oil  

20? 

22Q 

CQ 

o  844 

r    r 

Sap. 
Value. 

Viscos- 
ity at 
70°  F. 

Viscos- 
ity at 

212°  F. 

Flash 
Point. 

Fire 

Test. 

3/27/1  I. 

Mineral  lard  oil  cutting  oil 

6l 

183 

02 

384 

4^2 

SOME  SPECIFICATIONS  FOR  OILS. 
Engine  oils. 

1.  Flashing  point  above  400°  F. 

2.  It  must   be    a  pure  mineral  hydrocarbon  oil,  free  from 

adulteration. 

3.  Its  specific  gravity  must  be  between  26°  and  30°  Baume. 

4.  Its  viscosity  (compared  with  water  at  60°  F.,  using  a  P.R.R. 

standard  100    c.c.  pipette)  must  be,  when  determined 
at  80°  F.,  not  less  than  2.5. 

5.  The  oil  must  be  free  from  acids,  sulphur  compounds  or 

any  other  corrosive  substances,  and  free  from  dirt  or 
any  other  gritty  material. 


396  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

Heavy  Dark  Engine  Oil. 

1.  Flashing  point  above  450°  F. 

2.  Its  viscosity  (compared  with  water  at  60°  F.,  using  a  P.R.R. 

standard  100  c.c.  pipette),  when  determined  at  80°  F., 
must  not  be  less  than  2.5. 

3.  The  oil  must  be  free  from  all  sulphur  compounds,  acid  or 

any  other  corrosive  substances  of  any  kind,  and  free 
from  dirt  or  any  gritty  substances. 

4.  Its  specific  gravity  must  be  between  26°  and  30°  Baume. 

Cylinder  Oil. 

1.  It  must  have  a  flashing  point  of  not  less  than  550°  F. 

2.  Its  specific  gravity  must  be  between  25°  and  26°  Baume. 

3.  Its  viscosity  (compared  with  water  at  60°  F.,  using  a  P.R.R. 

standard  100  c.c.  pipette),  when  determined  at  330°  F., 
must  not  be  less  than  1.25. 

4.  It  must  contain  no  saponifiable  animal  oil,  and  be  a  pure 

mineral  hydrocarbon  oil,  free  from  adulterations. 

5.  The  oil  must  be  free  from  sulphur  compounds,  acids  or 

any  other  corrosive  substances  of  any  kind,  and  must 
be  free  from  dirt  or  any  gritty  substances. 

Journal  and  Roll  Neck  Grease. 

1.  It  must  be  free  from  all  dirt  and  grit  of  any  kind,  acid  or 

corrosive  substances. 

2.  It  must  be  absolutely  neutral  in  reaction  and  free  from 

metallic  oxides,  other  than  lime. 

Torch  Oil 

1.  It  must  have  a  flashing  point  of  not  less  than  125°  F. 

2.  It  must  show  a  fire  test  not  below  150°  F. 

3.  Its  specific  gravity  must  be  between  44°  and  48°  Baume 

at  60°  F. 

4.  It  must  not  become  cloudy  when  cooled  at  o°  F. 

5.  This  oil  must  be  pure  petroleum  oil,  free  from  dirt,  grit, 

lumps,  water,  etc. 


THE  TESTING  OF  LUBRICATING  OILS  397 

Paraffine  Oil. 

1.  This  oil  must  be  neutral  in  reaction,  free  from  all  dirt  or 

similar  substances,  and  may  have  a  flashing  point  as  low 
as  200°  F.     It  must  be  pure  petroleum  oil. 

2.  Its  viscosity  (compared  with  water  at  60°  F.,  using  a  P.R.R. 

standard  100  c.c.  pipette),  when  determined  at  60°  F.,. 
should  not  be  less  than  1.2. 
Screw  Cutting  Oil. 

1.  This  oil  shall  consist  of  paraffine  oil  of  about  27°  Baume 

gravity  compounded  with  not  less  than  25  per  cent  by 
weight  of  fat  oil,  cotton  seed  preferred. 

2.  The  compounded  oil  shall  have  a  flashing  point  not  below 

300°  F.  and  a  burning  point  not  above  425°  F. 

Fish  Oil. 

1.  It  must  have  a  flashing  point  of  not  lower  than  525°  F. 

2.  It  must  congeal  at  43°  F. 

3.  It  must  be  free  from  soaps  of  any  kind. 

4.  It  must  have  a  specific  gravity  of  21°  Baume. 

5.  It  must  be  free  from  dirt  and  impurities. 

Barrels  must  be  in  good  condition,  and  should  any  barrel 
contain  water,  dirt  or  other  impurities  it  will  be  rejected. 

NOTE.  The  foregoing  specifications  follow  very  closely  those  gotten  out  by  the 
Philadelphia  &  Reading  R.  R.  under  Robt.  Job. 

VISCOSITY  BY  THE  UNIVERSAL  STANDARD  SAYBOLT 

VlSCOSIMETER. 

The  following  viscosity  figures  were  recently  recommended 
to  the  author  by  a  chemist  of  much  experience  in  the  manufac- 
ture of  lubricants: 

Engine  oil  at  100°  F.,  150  to  200  viscosity;  average  160  to  180. 

Heavy,  dark  engine  oil  at  130°  F.,  175  to  250  viscosity;  average 
200. 

Cylinder  oil  at  212°  F.,  150  to  200  viscosity;  average  160  to 
170. 

Paraffine  oil  at  100°  F.,  no  to  150;  for  light  work,  100,  and  for 
heavy  work,  150  viscosity. 


CHAPTER  XIX. 

PART  II. 
THE  TESTING  OF  COAL. 

External  Moisture.  By  this  term  is  meant  the  rain,  snow, 
or  mine,  or  barge  water  adhering  to  the  surfaces  of  the  coal. 
For  this  determination  samples  should  be  put  at  once  into 
Mason  jars  supplied  with  screw  tops  and  rubber  washers  or 
gaskets.  The  jars  should  be  filled  at  the  place  of  sampling  and 
the  tops  screwed  down,  tightly,  on  the  rubber.  The  jars  can  then 
be  taken  to  the  laboratory  and  allowed  to  attain  the  room  tem- 
perature and  weighed  without  opening  them.  After  getting  this 
weight,  the  jars  are  opened  and  the  contents  are  spread  out  in 
thin  layers,  taking  care  that  this  operation  is  performed  without 
the  smallest  loss  of  the  weighed  coal.  The  opened  jars  are 
placed  in  a  bath  of  hot  air  to  dry.  The  rubbers  are  removed  and 
marked  the  same  as  their  respective  jars  during  the  drying  of  the 
latter  at  a  temperature  of  about  80°  C.  The  contents  of  the  jars 
are  also  labeled  and  are  dried,  without  any  crushing,  at  a  tem- 
perature of  1 00°  C.  for  several  hours  until  all  evidences  of  ex- 
ternal dampness  is  gone  and  the  fines  in  the  samples  have  a 
tendency  to  be  dusty.  The  tests  are  then  returned  to  their 
respective  containers;  the  rubbers  and  tops  are  also  returned  to 
their  jars.  The  jars  and  their  dried  contents  are  again  weighed 
after  regaining  the  room  temperature.  The  dry,  empty  jars  with 
caps  and  rubbers  on  were  also  weighed  in  the  meantime.  The 
weight  of  the  jars  and  the  wet  contents  less  the  weight  of  the 
jars  and  the  dry  contents  equals  the  weight  of  external  moisture. 
The  weight  of  the  external  moisture  multiplied  by  100  and  divided 
by  the  weight  of  the  corresponding  jar  and  wet  contents,  from 
which  has  been  deducted  the  weight  of  the  dry  empty  jar,  con- 
stitutes the  per  cent  of  external  moisture.  All  weights  referred 

398 


THE  TESTING  OF   COAL  399 

to  are  taken  with  the  caps  and  rubbers  on  the  jars  and  are  made 
on  a  torsion  balance.  This  balance  is  of  10  kilos  capacity  and 
sensitive  to  a  tenth  of  a  gram.  For  these  tests  large  samples  are 
taken,  from  i  to  2  pounds. 

Internal  Moisture.  The  sample  after  being  used  for  the  determi- 
nation of  the  external  moisture  is  crushed  to  100  mesh  or  finer  and 
i  gram  of  the  powdered  coal  is  dried  for  one  hour  at  105°  C.  The 
loss  of  weight  constitutes  the  internal  moisture  which  is  reported 
in  percentage.  The  sample  is  dried  in  a  20  c.c.  platinum  crucible. 

Volatile  Matter.  Place  the  crucible  containing  the  sample  on 
which  the  internal  moisture  determination  was  made  in  a  ni- 
chrome  triangle  supported  8  cm.  above  the  top  of  a  Bunsen 
burner  and  play  a  flame  10  cm.  high  back  and  forth  across  the 
bottom  of  the  crucible  which  is  covered  with  a  tightly  fitting 
lid.  Continue  this  heating  for  4  minutes.  Then  place  the 
burner  directly  under  the  crucible  with  the  flame  stationary  and 
increase  the  length  of  the  flame  to  20  cm.  Continue  to  heat 
for  7  minutes  more.  Cool  in  a  desiccator  and  weigh.  The  loss 
of  weight  constitutes  the  volatile  matter. 

The  Committee  on  Coal  Analysis  of  the  American  Society  for 
Testing  Materials  and  the  American  Chemical  Society  recom- 
mend that  the  volatile  matter  be  determined  in  a  10  gram  plati- 
num crucible,  using  a  capsule  lid,  that  is,  one  that  fits  inside  the 
crucible.  The  crucible  and  its  one  gram  sample  can  then  be  placed 
in  a  muffle  heated  to  950°  C.  and  maintained  at  this  tempera- 
ture for  7  minutes.  The  author  would  prefer  to  use  an  electri- 
cally heated  muffle  furnace*  which  every  laboratory  should  have, 
without  fail,  and  can  make  at  a  low  cost  for  this  purpose.  See 
Making  and  Repairing  of  Laboratory  Electric  Furnaces,  page  419. 
The  crucible  is  placed  on  a  ni-chrome  triangle  support  bent  so  as 
to  keep  the  bottom  of  the  crucible  clear  of  the  floor  of  the  furnace. 

Fixed  Carbon  and  Ash.  The  residue  remaining  in  the  crucible 
after  the  determination  of  the  volatile  matter  is  heated  to  a  dull 
red  and  maintained  at  this  heat  until  all  carbon  is  burned  away. 

*  The  electric  muffle  is  ventilated  by  a  regulated  stream  of  air  drawn  from  the 
compressed  air  pipe. 


400  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  operation  can  be  facilitated  by  supporting  the  crucible  in  a 
slanting  position  with  the  lid  only  partly  covering  it.  Also 
occasional  stirring  of  the  mass  in  the  crucible,  using  great  care  to 
prevent  loss  of  the  ash,  will  expedite  the  removal  of  the  carbon. 
When  the  ash  has  assumed  a  uniform  grey  or  reddish  color  free 
of  all  black  material,  the  crucible  is  transferred  to  a  desiccator, 
cooled  and  weighed.  The  loss  of  weight  due  to  this  removal  of 
carbon  is  calculated  to  percentage  as  fixed  carbon,  on  a  basis 
of  one  gram. 

The  ash  found  in  the  fixed  carbon  determination  can  be 
calculated  as  such  to  percentage  or  the  ash  can  be  gotten  on  a 
separate  one  gram  sample.  The  freshly  weighed  sample  is  at 
first  smoked  off  on  a  Bunsen  burner  as  described  in  the  determi- 
nation of  the  volatile  matter.  The  crucible  is  then  raised  to  a 
dull  red  heat  after  all  smoking  is  over  and  the  heating  is  continued 
as  already  described.  The  extensive  preliminary  report  of  the 
committee  above  mentioned  can  be  found  in  the  Journal  of 
Industrial  and  Engineering  Chemistry,  Vol.  5,  No.  6,  pages 


Heat  Units.  Any  of  the  well  known  calorimeters  can  be  used  for 
this  work.  As  the  details  of  the  operations  of  the  instruments  are 
always  furnished  with  the  latter,  it  seems  quite  unnecessary  to 
repeat  them  here.  The  author  would  recommend  that  operator 
check  his  work  and  the  instrument  against  some  convenient 
material  of  known  heat  units.  For  this  work  the  writer  has  a 
standard  coal  powder  on  which  the  heat  units  were  determined 
by  the  U.  S.  Bureau  of  Standards  and  a  sample  of  the  standard 
benzoic  acid  which  is  also  furnished  by  the  same  institution  for 
a  small  fee.  The  checking  should  be  done  at  frequent  intervals 
during  the  operation  of  the  calorimeter. 

Sulphur.  Grind  together  in  an  agate  mortar  4  grams  of 
magnesia  and  2  grams  of  sodium  carbonate  until  an  intimate 
mixture  of  these  materials  is  obtained.  Mix  thoroughly  with 
four-fifths  of  this  mixture  i  gram  of  the  finely  powdered  coal 
in  a  platinum  or  porcelain  crucible.  Then  put  the  other  one- 
fifth  of  the  mixture  as  a  layer  on  top  of  the  mixture  of  coal 


THE  TESTING  OF   COAL  401 

powder,  magnesia  and  sodium  carbonate.  Place  the  crucible 
in  an  inclined  position  over  the  low  flame  of  a  Bunsen  burner. 
Move  the  flame  slowly  back  and  forth  under  the  crucible  until 
it  is  very  gradually  brought  to  a  low  red  heat  on  the  bottom, 
and  the  mixture  glows  faintly  under  the  top  layer,  as  can  be 
ascertained  by  giving  the  mass  a  slight  stir  with  a  ni-chrome 
wire.  Continue  this  low  heating  until  all  black  due  to  carbon 
is  gone.  Stir  the  mass  at  intervals. 

Transfer  the  residue  in  the  crucible,  when  the  carbon  is  gone, 
to  a  casserole.  Rinse  out  the  crucible  with  about  40  c.c.  of 
water,  adding  the  rinsings  to  the  residue  in  the  casserole.  Add 
70  c.c.  of  bromine  water  to  the  casserole,  cover  it  with  a  watch 
glass,  boil  10  minutes,  remove  the  cover,  add  50  c.c.  of  cone.  HC1 
and  evaporate  to  dryness.  Cool,  add  20  c.c.  of  cone.  HC1,  heat, 
add  100  c.c.  of  water,  filter  out  any  insoluble  matter  and  wash  with 
dilute  HC1.  Dilute  the  filtrate  and  washings  to  300  c.c.  Heat 
to  boiling  and  add  25  c.c.  of  a  saturated  solution  of  barium 
chloride  diluted  with  75  c.c.  of  water.  Let  the  barium  sulphate 
settle  for  several  hours,  preferably  over  night.  Finish  as  in 
gravimetric  sulphur  in  steels. 

For  a  check  the  operator  can  carry  through  the  factor  weight 
as  recommended  by  the  before  mentioned  committee.  The 
above  is  a  modified  form  of  the  Eschka  method.  Blanks  should 
be  carried  through  all  of  the  above  operations  and  deducted. 

For  a  check  method  i  gram  of  the  powdered  coal  can  be  fused 
in  the  calorimeter  bomb  with  sodium  peroxide  and  potassium 
chlorate  per  directions  given  with  the  calorimeter.  Also  J  gram 
of  coal  can  be  fused  in  a  platinum  crucible  with  a  mixture  of  15 
grams  of  sodium  carbonate  and  5  grams  of  potassium  nitrate, 
dissolved  out  in  water,  transferred  to  a  casserole,  acidulated 
with  HC1  and  finished  as  in  the  Eschka  method.  A  further 
check  method  is  to  fuse  0.5  gram  of  the  powdered  coal  with 
a  mixture  of  15  grams  of  sodium  peroxide  and  7.5  grams  of 
sodium  carbonate  in  an  iron  crucible.  The  melt  is  dissolved 
out  in  water,  acidulated  with  HC1  and  finished  as  in  the  other 
methods. 


402  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

The  barium  sulphate,  obtained  by  any  of  the  methods  given, 
must  be  moistened  with  a  few  drops  of  dilute  sulphuric  acid 
after  it  has  been  ignited  free  of  carbon.  It  is  then  ignited  again 
to  free  it  of  the  excess  of  the  sulphuric  acid.  This  insures 
against  the  presence  of  barium  sulphite  due  to  the  reducing 
action  of  the  burning  filter  paper. 

Phosphorus.  Obtain  the  ash  from  1.63  grams  of  the  coal  by 
burning  the  same  on  a  low  flame  in  a  20  gram  platinum  crucible. 
Fuse  the  ash  with  20  times  its  weight  of  sodium  carbonate 
and  o.ioo  gram  of  niter.  Dissolve  out  the  fusion  with  water, 
and  transfer  it  to  a  casserole  and  acidulate  with  HC1,  keeping  the 
casserole  covered  to  avoid  loss.  Heat  until  all  spraying  is  over; 
evaporate  to  dryness,  cool,  redissolve  by  first  heating  with  10  c.c. 
of  cone.  HC1.  Add  50  c.c.  of  water.  Heat,  filter,  add  a  few 
drops  of  ferric  chloride  solution  unless  there  is  enough  ir9n  pres- 
ent to  give  a  red  precipitate  with  ammonia  in  the  filtrate  and 
washings.  Wash  the  ammonia  precipitate  a  few  times  with  water 
and  then  dissolve  it  off  the  filter  with  20  c.c.  of  1.20  nitric  acid. 
Use  the  acid  hot  and  pour  it  back  on  the  filter  until  all  of  the 
iron  hydroxide,  which  will  carry  all  of  the  phosphorus,  is  dis- 
solved off  the  filter.  Wash  the  filter  with  some  i  :  40  nitric  acid 
about  twenty  times  or  until  the  washings  do  not  give  an  appre- 
ciable iron  test  with  KCNS.  Evaporate  the  filtrate  and  wash- 
ings to  15  c.c.  Add  15  c.c.  of  water,  boil  with  a  slight  excess  of 
KMnC>4  solution,  clear  the  excess  of  manganese  oxide  away  with 
ferrous  sulphate,  add  molybdate  to  the  hot  solution  and  finish 
as  in  steel. 

Those  who  are  interested  in  more  elaborate  details  are  referred 
to  the  preliminary  report  of  the  committee  already  referred  to, 
or  to  Technical  Paper  No.  8  of  the  Department  of  the  Interior* 
Bureau  of  Mines,  Washington,  D.  C.,  Entitled  Methods  of 
Analyzing  Coal  and  Coke,  by  Frederick  M.  Stan  ton  and  Arne  C. 
Fieldner.  The  authors  also  give  the  method  they  use  for  the 
determination  of  nitrogen  in  coal.  The  preliminary  report  of  the 
Committee  on  Coal  Analysis  can  be  found  in  Vol.  5,  No.  6,  of 
the  Journal  of  Industrial  and  Eng.  Chemistry. 


THE  TESTING  OF  COAL  403 

Coke  Analysis. 

Carbon.  The  author  determines  the  total  carbon,  as  in  the 
analysis  of  graphite,  by  burning  0.200  gram  of  the  coke  in  the 
electric  combustion  furnace. 

The  sulphur  is  obtained  by  fusing  0.5  gram  of  the  coke  in  an 
iron  crucible  with  15  grams  of  sodium  peroxide  mixed  with  10 
grams  of  sodium  carbonate.  The  fusion  is  then  dissolved  out 
with  water  and  finished  as  given  for  sulphur  in  coal. 

The  ash  is  obtained  as  in  coal. 


CHAPTER  XX. 

PART  I. 

THE  PERCENTAGE  REDUCTION  OF  A  SUBSTANCE  IN  SOLU- 
TION TO  ANY  DESIRED  PERCENTAGE. 

LET  P  =  the  percentage  of  the  substance  in  the  concentrated 
solution. 
'   Let  p    =  the  lower  and  desired  percentage  of  the  substance. 

Let  A    =  the  specific  gravity  of  the  concentrated  solution. 

Let  W  =  the  amount  of  water  necessary  to  add  to  i  c.c.  of 
the  cone,  solution  to  reduce  it  to  the  desired  lower  percentage. 


Then 


CALCULATIONS. 

Suppose  the  specific  gravity  of  a  given  sample  of  nitric  acid 
is  found  by  means  of  a  hydrometer  to  be  1.400  at  a  temperature 
of  20°  C.  By  table  No.  i  we  find  that  the  difference  in  specific 
gravity  for  i°  C.  between  1.37  sp.  gr.  and  1.405  is  from  0.0013  to 
0.0014,  or  a  total  difference  of  o.oooi  for  a  variation  of  0.035 
in  specific  gravity.  Now  1.400  is  0.030  above  1.37  in  specific 
gravity,  therefore  the  correction  for  i  degree  at  1.400  is  0.0013 
plus  ff  of  o.oooi,  or  0.0013  plus  0.000085,  or  0.001385.  Since 
the  temperature  was  20  degrees,  then  the  specific  gravity  of 
the  given  acid  if  cooled  to  15  degrees  would  be  1.40  plus  0.00138 
X  5,  or  1.4069.  By  the  table  we  find  that  the  nearest  specific 
gravity,  or  1.405,  gives  a  percentage  of  66.40.  Further,  the 
percentage  correction  at  this  point  for  o.ooi  of  specific  gravity 
is  0.220.  Therefore,  the  percentage  of  the  given  concentrated 
acid  at  15  degrees  would  be  66.40  plus  0.220  X  1.9,  or  66.4  plus 
0.418,  or  66.818,  or  P  in  the  reduction  formula. 

404 


THE   PERCENTAGE   REDUCTION  OF  A   SUBSTANCE,  ETC.       405 

For  example,  if  it  is  desired  to  reduce  this  66.818  per  cent  acid 
at  15  degrees  to  32  per  cent  acid  at  15  degrees,  then  we  have 
66.818  -  32.00  x  T  34,818  x  Qr  i  o8g  x  x 

32.00  32 

or  1.530,  or  every  c.c.  of  the  acid  requires  1.5307  c.c.  of  water 
to  reduce  it  to  32  per  cent  at  15°  C.  By  consulting  table  No.  2 
it  will  be  seen  that  1000  c.c.  acid  of  1.407  specific  gravity  requires 
1531.8  c.c.  of  water  to  reduce  it  to  32  per  cent  acid  at  15°  C. 

In  like  manner,  if  it  is  required  to  obtain  20  per  cent  acid  from 

.,    66.818  -  20  46.818  v 

66.818  per  cent  acid: X  1.4069,  or- X  1.4069, 

20  20 

or  2.3409  X  1.4069,  or  3.2934.  That  is,  i  c.c.  of  66.818  per  cent 
acid  requires  3.2934  c.c.  of  water  to  dilute  it  to  20  per  cent 
acid  at  15°  C. 

USE  OF  TABLE  No.  2. 

Having  by  means  of  table  No.  i  calculated  the  observed 
specific  gravity  to  15  degrees,  then  from  table  No.  2  the  amount 
of  water  required  to  reduce  such  an  acid  to  32  per  cent  or  20  per 
cent  is  read  either  direct  or  by  interpolation. 

In  a  similar  way  one  can  reduce  concentrated  ammonia  to  any 
desired  lower  percentage,  the  only  difference  being  that  in  cal- 
culating to  15°  C.  the  correction  for  percentage  is  sub  tractive 
instead  of  additive  as  in  the  case  of  acids,  the  reason,  of  course, 
being  that  the  greater  the  density  of  ammonia  solution  in  water, 
the  lower  the  percentage  of  NH3  therein. 

If  one  needs  to  prepare  from  concentrated  ammonia  an  11.50 
per  cent  solution,  first,  dilute  two  parts  of  the  former  with  one 
part  of  water  and  cool  to  the  room  temperature.  Let  the  read- 
ing be  0.9385  at  23°  C.  The  correction  for  i°  C.  at  0.938  by 
table  No.  3  is  0.0004  for  specific  gravity.  The  total  correction 
for  the  8  degrees  is  0.0004  X  8,  or  0.0032.  The  specific  gravity 
of  the  ammonia  at  15  degrees  is  therefore  0.9385  plus  0.0032,  or 
0.9417.  By  the  table  the  nearest  lower  specific  gravity  is  0.940, 
which  corresponds  to  15.63  per  cent  ammonia.  The  percentage 
correction  for  o.ooi  of  specific  gravity  at  this  point  is  0.295. 


406  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

.Therefore,  the  total  correction  is  0.295  X  1.7,  or  0.5015.  Hence, 
the  percentage  for  a  specific  gravity  of  0.9417  is  15.63  —  0.5015, 
or  15.1285.  To  reduce  this  percentage  to  11.50  the  formula 
gives  the  following: 

15.128  —  11.50  v  v         r   i  • 

— •*-  X  0.9417  equals  0.297,  or  x  uter  of  this  ammonia 
11.50 

would  require  297  c.c.  of  water  to  dilute  it  to  11.50  per  cent 
at  15°  C. 

For  further  illustration,  suppose  it  is  necessary  to  obtain  the 
percentage  of  ammonia  corresponding  to  a  specific  gravity  of 
0.947  at  22  degrees.  The  correction  for  specific  gravity  per  i 
degree  of  temperature  at  the  nearest  point  in  the  table  (0.946) 
is  0.00036.  As  the  reading  was  taken  7  degrees  above  the  15 
degrees,  then  the  total  correction  is  0.00036  X  7,  or  0.00252,  and 
the  corrected  reading  is  0.947  plus  0.00252,  or  0.9495.  The  near- 
est lower  specific  gravity  in  table  No.  3  is  0.948,  being  equiva- 
lent to  a  percentage  of  13.31.  Now  the  correction  for  percentage 
at  this  point  is  0.285  f°r  every  o.ooi  of  specific  gravity.  The 
total  correction  is  0.285  X  1.5,  or  0.427.  The  percentage  of 
the  ammonia  for  0.9495  at  15  degrees  is  13.31  —  0.427,  or  12.88 
per  cent. 


THE  PERCENTAGE  REDUCTION  OF  A   SUBSTANCE,  ETC.       407 


TABLE   i. 
AQUEOUS  SOLUTIONS  OF  NITRIC  ACID. 

From  a  Table  by  Lunge  and  Rey.     Specific  Gravities  and  Percentages  HNOj. 


Difference 

Difference 

Difference 

Difference 

Specific 
Gravity 

Percent- 

in Specific 
Gravity 

in  Percent- 
age for 

Specific 
Gravity 

Percent- 

in Specific 
Gravity 

in  Percent- 
age for 

'?- 

age 
HNO3. 

for  i°  C. 
between 

O.OOI 

Specific 

•¥* 

age 
HN03. 

for  i°  C. 
between 

O.OOI 

Specific 

13°  and  17° 

Gravity. 

13°  and  17° 

Gravity. 

•    1-055 

9-84 

0.0003 

.280 

44.41 

0.0009 

0.154 

1.  060 

10.68 

0.0003 

0.168 

.285 

45-18 

O.OOIO 

0.154 

.065 

11.51 

0.0003 

o.  166 

.290 

45-95 

O.OOIO 

0.154 

.070 

12.33 

0.0003 

o.  164 

•  295 

46.72 

O  .  OOIO 

0.154 

•075 

I3-I5 

0.0004 

o.  164 

.300 

47-49 

O.OOIO 

0.154 

.080 

13-95 

0.0004 

o.  160 

•305 

48.26 

O.OOIO 

0.154 

•085 

14-74 

0.0004 

0.158 

.310 

49.07 

O.OOIO 

o.  162 

.090 

15-53 

0.0004 

0.158 

•315 

49.89 

O.OOI  I 

0.164 

•095 

16.32 

0.0004 

0.158 

.320 

50-71 

O  .  OOI  I 

0.164 

.IOO 

17.11 

o  .  0004 

0.158 

•325 

5I-S3 

O.OOI  I 

o.  164 

.105 

17.89 

0.0005 

0.156 

•330 

52.37 

O.OOI  I 

0.168 

.  no 

18.67 

0.0005 

o.  156 

•335 

53-22 

O.OOII 

o.  170 

•  115 

19-45 

0.0005 

0.156 

-340 

54-07 

O.OOI  I 

o.  170 

.  1  20 

20.23 

0.0005 

0.156 

-345 

54-93 

O.OOII 

o.  172 

•  125 

21  .OO 

0.0005 

o.i54 

•350 

55-79 

O.OOII 

o.  172 

.130 

21-77 

0:0005 

o.i54 

•355 

56.66 

O  .  OOI  2 

0.174 

•  135 

22.54 

0.0006 

o.i54 

.360 

57-57 

0.0012 

0.182 

.  140 

23-31 

0.0006 

o.i54 

-365 

58.48 

O.OOI  2 

0.182 

•145 

24.08 

0.0006 

0.154 

-370 

59-39 

0.0013 

0.182 

.150 

24.84 

0.0006 

0.152 

•375 

60.30 

0.0013 

0.182 

•155 

25.60 

0.0006 

o.  152 

-380 

61  .  27 

0.0013 

0.194 

.160 

26.36 

0.0006 

0.152 

-385 

62.24 

0.0013 

0.194 

.165 

27.12 

0.0007 

0.152 

-390 

63-23 

0.0013 

0.198 

.170 

27.88 

0.0007 

0.152 

•395 

64.25 

0.0013 

0.204 

•175 

28.63 

0.0007 

0.150 

.400 

65-30 

0.0013 

O.  2IO 

.180 

29.38 

0.0007 

0.150 

-405 

66.40 

0.0014 

O.  22O 

-185 

30.13 

0.0007 

0.150 

.410 

67.50 

0.0014 

O.  22O 

.190 

30.88 

0.0007 

0.150 

-4i5 

68.63 

0.0014 

O.226 

•195 

31.62 

0.0007 

o.  150 

.420 

69.80 

0.0014 

0.234 

.200 

32-36 

0.0007 

0.148 

•425 

70.98 

0.0014 

0.236 

.205 

33-09 

0.0008 

o.  146 

•430 

72.17 

0.0014 

0.238 

.210 

33-82 

0.0008 

o.  146 

•435 

73-39 

0.0014 

0.244 

•215 

34-55 

0.0008 

o.  146 

•440 

74-68 

0.0015 

0.258 

.220 

35-28 

0.0008 

o.  146 

•  445 

75-98 

0.0015 

O.26O 

.225 

36.03 

0.0008 

0.150 

•  450 

77-28 

0.0015 

o.  260 

.230 

36.78 

0.0008 

0.150 

•455 

78.60 

0.0015 

0.264 

•235 

37-53 

0.0008 

o.  150 

.460 

79.98 

0.0015 

0.276 

.240 

38.29 

0.0008 

o.  152 

•  465 

81.42 

0.0015 

0.288 

•245 

39-05 

0.0008 

0.152 

•470 

82.90 

0.0015 

0.296 

.250 

39-82 

0.0009 

0.154 

•475 

84.45 

0.0015 

0.310 

-255 

40.58 

o  .  0009 

0.152 

.480 

86.05 

0.0015 

0.320 

.260 

41-34 

0.0009 

0.152 

-485 

87.70 

0.0015 

0.330 

.265 

42.  10 

0.0009 

o.  152 

.490 

89.60 

0.0015 

O.42O 

.270 

42.87 

0.0009 

0.154 

•495 

91  .60 

0.0016 

O.4OO 

•275 

43-64 

0.0009 

0.154 

-500 

94.09 

0.0016 

0.498 

408 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


TABLE   2. 
DILUTION  OF  CONCENTRATED  NITRIC  ACID. 

To  20  and  32  Per  Cent. 


Specific 
Gravity 
HNO3 
at  15°  C. 

Water  Added  to 

IOOO  C.C. 

Variation 
in  Weight, 
Water  for 
i°C. 

Specific 
Gravity 
HN03 
at  15°  C. 

Water  Added  to 

IOOO  C.C. 

Variation, 
in  Weight. 
Water,  for 
i°C. 

20  Per 
Cent. 

32  Per 
Cent. 

20  Per 
Cent. 

32  Per 
Cent. 

•395 

3086.4 

1405-9 

1.38 

1-433 

3790.5 

1831.7 

.88 

.396 

3I03-3 

1415.8 

1-39 

1-434 

3810.6 

1843-9 

.90 

•397 

3120.2 

1425.7 

1.40 

1-435 

3830.7 

1856.1 

.91 

.398 

3I37.I 

1435  -  7 

1.41 

-436 

3852.0 

1869.0 

.92 

•399 

3154.0 

1445-6 

1.42 

-437 

3873.3 

1881.9 

•94 

.400 

3171.0 

1456.9 

i-43 

-438 

3894.6 

1894.8 

.96 

.401 

3188.7 

1467.1 

1.44 

•439 

39I5.9 

1907.7 

.98 

.402 

3206.4 

1477-4 

1.46 

-440 

3937-0 

1920.6 

2.OO 

.403 

3224.1 

1487-6 

1-47 

-441 

3958.5 

1933  •  7 

2.02 

.404 

3241-8 

1497.9 

1.48 

-442 

398o.o 

1946.8 

2-03 

.405 

3259-6 

1510.4 

i-49 

-443 

4001.5 

1959-9 

2-05 

.406 

3277.8 

1521.1 

i-5o 

•  444 

4023.0 

i973-o 

2.06 

.407 

3295-5 

I53I-8 

1-52 

•  445 

4044  .  6 

1986.0 

2.07 

.408 

3313-2 

1542.5 

i-53 

.446 

4066  .  2 

1999.2 

2.09 

.409 

3330-9 

1553-2 

i-55 

•  447 

4087.8 

2012.4 

2.IO 

.410 

3348.8 

1564.2 

i-57 

-448 

4109.4 

2025.6 

2.  II 

.411 

3367.2 

1575-3 

1-58 

-449 

4I3I.O 

2038  .  8 

2.  12 

.412 

3385.6 

1586.4 

i-59 

-450 

4152.8 

2051.8 

2.13 

.413 

3404.0 

1597-5 

i.  60 

•451 

4175  -1 

2065.2 

2-15 

.414 

3422.4 

1608.  6 

1.61 

-452 

4I97-4 

2078.6 

2.17 

.415 

3440.6 

1619.7 

1.62 

-453 

4219.7 

2092.0 

2.19 

.416 

3459-6 

1631.2 

1-63 

-454 

4242.O 

2105.4 

2.21 

.417 

3478-6 

1642.7 

1-65 

-455 

4263  .  2 

2118.  8 

2.  22 

.418 

3497-6 

1654.2 

1.66 

.456 

4286.3 

2132.9 

2.24 

.419 

35i6.6 

1665.7 

1.68 

•457 

4309.4 

2147.0 

2.25 

.420 

3535-8 

1677.4 

1.70 

.458 

4332.5 

2161  .  i 

2.26 

.421 

3555-1 

1689.1 

1.70 

•459 

4355-6 

2175.2 

2.27 

.422 

3574-4 

1700.8 

1.70 

.460 

4378.5 

2189.  i 

2.28 

-423 

3593-7 

1712.5 

1.70 

.461 

4402  .  6 

2203.7 

2.30 

.424 

3613.0 

1724.2 

1.70 

.462 

4426  .  7 

2218.3 

2.32 

•425 

3632-3 

1735-8 

1.72 

-463 

4450  -  8 

2232.9 

2-34 

.426 

3651-9 

1747.6 

1.72 

-464 

4474-9 

2247-5 

2.36 

.427 

3671-5 

1759-4 

1-74 

•465 

4499-0 

2262.3 

2.38 

.428 

3691.1 

1771.2 

1.77 

.466 

4523-8 

2277.5 

2.41 

.429 

3710.7 

1783.0 

1.79 

•467 

4548  .  6 

2292.7 

2.44 

•430 

3730.2 

I795-I 

1.82 

.468 

4573-4 

2307-9 

2.47 

•431 

3750.3 

1807.3 

1.84 

.469 

4598  -  2 

2323.1 

2.50 

1-432 

3770-4 

1819.5 

1.86 

.470 

4623.2 

2338-3 

2-55 

THE  PERCENTAGE  REDUCTION  OF  A   SUBSTANCE,  ETC.       409 


TABLE  3. 
SPECIFIC  GRAVITIES  OF  AMMONIA  SOLUTIONS. 

Lunge  and  Wiernik. 


Specific 
Gravity 
at  15°  C. 

Per  Cent 
NH3. 

Difference 
in  Specific 
Gravity 
for  i°  C. 

Difference 
in  Per  Cent 
for  o.ooi 
Specific 
Gravity. 

Specific 
Gravity 
at  15°  C. 

Per  Cent 
NH3. 

Difference 
in  Specific 
Gravity 
for  i°  C. 

Difference 
in  Per  Cent 
for  o.ooi 
Specific 
Gravity. 

0.980 

4.80 

o  .  00023 

0.930 

18.64 

0.00042 

0.305 

0.978 

5-30 

0.00023 

0.250 

0.928 

19.25 

o  .  00043 

0.305 

0.976 

5-80 

0.00024 

0.250 

0.926 

19.87 

o  .  00044 

0.310 

0-974 

6.30 

o  .  00024 

o.  250 

0.924 

20.49 

o  .  00045 

0.310 

0.972 

6.80 

0.00025 

o.  250 

0.922 

21  .12 

o  .  00046 

0.315 

0.970 

7-31 

0.00025 

0.255 

0.920 

21-75 

0.00047 

0.315 

0.968 

7.82 

0.00026 

0.255 

0.918 

22.39 

o  .  00048 

0.320 

0.966 

8-33 

0.00026 

0.255 

0.916 

23-03 

o  .  00049 

0.320 

0.964 

8.84 

0.00027 

0.255 

0.914 

23.68 

o  .  00050 

0.325 

0.962 

9-35 

0.00028 

0.255 

0.912 

24-33 

0.00051 

0.325 

0.960 

9.91 

o  .  00029 

0.280 

0.910 

24.99 

0.00052 

0.330 

0.958 

10.47 

o  .  00030 

0.280 

0.908 

25.65 

o  .  00053 

0.330 

0.956 

11.03 

0.00031 

0.280 

0.906 

26.31 

o  .  00054 

0.330 

0-954 

ii  .60 

0.00032 

0.285 

0.904 

26.98 

0.00055 

o-335 

0.952 

12.17 

o  .  00033 

0.285 

0.902 

27.65 

0.00056 

0-335 

0.950 

12.74 

o  .  00034 

0.285 

0.900 

28-33 

0.00057 

0.340 

0.948 

i3-3i 

0.00035 

0.285 

0.898 

29.01 

0.00058 

0.340 

0.946 

13.88 

0.00036 

0.285 

0.896 

29.69 

0.00059 

0.340 

0.944 

14.46 

0.00037 

o.  290 

0.894 

30.37 

o  .  00060 

0.340 

0.942 

15-04 

0.00038 

0.290 

0.892 

31-05 

0.00060 

0.340 

0.940 

15-63 

0.00039 

0.295 

0.890 

31-75 

0.00061 

0.350 

0.938 

16.22 

0.00040 

0.295 

0.888 

32.50 

0.00062 

o-375 

0.936 

16.82 

0.00041 

0.300 

0.886 

33-25 

0.00063 

0-375 

0-934 

17.42 

0.00041 

0.300 

0.884 

34-io 

0.00064 

0-425 

0.932 

18.03 

0.00042 

0.305 

0.882 

34-95 

0.00065 

0.425 

CHAPTER  XX. 

PART  II. 

PLAN  AND  VIEWS  OF  CHEMICAL  LABORATORY  FOR  STEEL 
WORKS  PRACTICE. 

THE  working  drawings  show  an  extension  planned  by  the 
author,  and  recently  added  to  the  laboratory  of  the  Park  Works 
of  the  Crucible  Steel  Co.  of  America.  (Pages  411  and  418.) 

Central  double  tables  are  located  at  D,  D,  and  single  side 
tables  at  H,  F,  E,  J,  7,  and  a  single  center  one  at  G,  Fig.  29-1. 
Tables  D,  D,  and  E  are  supplied  with  gas  at  8  oz.  pressure,  com- 
pressed air  at  about  eighty  pounds  and  water  as  shown.  At 
the  small  deep  stone  sinks  on  the  ends  of  the  tables  are  brass 
water  power  pumps.  Illustration  15,  page  247,  gives  a  view  of 
one  of  these  suction  outfits  where  four  chromium- vanadium  tests 
can  be  filtered  through  porous  alundum  thimbles,  connected  to 
one  pump  by  means  of  a  glass  manifold.  The  circles  represent 
the  large  wash  bottles  that  are  placed  on  high  pedestals. 

View  30  shows  these  bottles  above  the  tables.  No.  31  shows 
the  hoods.  The  halves  of  D,  D,  Fig.  29-1,  facing  the  center 
isle  are  used  for  combustion  work.  There  is  abundant  room 
for  eight  outfits,  four  on  each  half.  View  32  shows  four  com- 
bustion furnaces  with  trains.  The  other  halves  of  D,  D,  are 
for  general  analytical  work  and  serve  the  hoods  C  and  B, 
Fig.  29-1. 


410 


PLAN  AND  VIEWS  OF,  CHEMICAL  LABORATORY,  ETC.      411 


.12  i  18  Ventilators  from 
_J  ceiling  to  roof  j__j 


29-1. 


1^  Stone 


1- Table  Req'd-H-1 

FIG.  29-2. 


412 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


PLAN  AND   VIEWS  OF   CHEMICAL  LABORATORY,  ETC.         413 


414  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


PLAN  AND  VIEWS  OF   CHEMICAL  LABORATORY,  ETC.      415 


VIEW  33. 


VIEW  34. 


416 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


All  hoods  are  equipped  with  water  and  extra  heavy  lead  waste 
pipes  for  condensers.  View  33  shows  one  of  these  brass  water 
cocks  of  which  there  are  two  in  each  division  of  the  hoods.  View 


FIG.  35. 

33  also  shows  the  way  in  which  the  gas  is  distributed  to  the 
various  burners  from  gas  cocks  concealed  in  the  hood  cupboards 
below.  All  working  surfaces  of  the  hoods  and  the  tables  are 
covered  with  stone  slabs.  All  heating  apparatus  is  placed  on  an 
upper  slab  set  on  wooden  cross  pieces  leaving  an  air  space  of 
about  i^  inches.  This  removes  danger  of  the  stone  slabs  being 
cracked  by  radiated  heat.  The  back  walls  of  hoods  are  of  acid- 
proof  brick  with  a  white  surface  as  shown  in  Views  31,  33,  34. 
The  latter  show  the  way  the  hoods  are  fitted  with  sliding  doors 
and  are  framed  with  cabinet  finished  straight  sawed  oak.  The 
sliding  doors  the  author  has  found  to  be  far  superior  to  any 
others.  The  hoods  along  the  walls  of  the  laboratory  are  much 
to  be  preferred  to  center  hoods.  The  latter  cut  off  the  light,  do 
not  have  a  good  draught  and  cannot  be  backed  with  acid-proof 
material.  Again  the  center  hood  is  peculiarly  subject  to  dirt 


PLAN  AND  VIEWS  OF   CHEMICAL  LABORATORY,  ETC.      417 

dropping  from  its  upper  parts  and  its  flues.  If  bits  of  mortar 
drop  from  flues,  slanting  sash  can  be  set  up  as  shown  in  the 
hood  at  the  rear  of  View  34.  These  frames  are  supported  on 
iron  rods  and  can  be  removed  in  a  few  moments  when  it  is 
desired  to  clean  out  the  hoods.  All  tables,  hoods  and  exposed 
floor  lines  have  stone  baseboards  to  prevent  the  marring  of 
the  woodwork  when  the  floors  are  mopped  or  scrubbed.  The 
large  sinks  near  the  doorways  are  made  of  heavy  acid-proof 
stoneware.  The  nipple  at  the  outlet  of  the  sink  fits  into  a  terra- 
cotta sewer  via  a  trap  of  the  same  material.  All  joints  are 
caulked  with  oakum  and  on  top  of  the  latter  is  poured  hot 
asphaltum.  The  sinks  of  this  description  are  practically  in- 
destructible. Fig.  35  gives  the  author's  design  and  dimensions 
of  this  acid  and  alkali  proof  sink.  The  sewer  from  such  a 
sink  should  never  lead  away  from  it  in  a  horizontal  direction. 
The  terra-cotta  sewer  from  any  sink  into  which  acid,  alkali 
or  any  corrosive  waste  is  poured  should  drop  vertically  to  the 
basement  to  prevent  stoppages  and  leaks.  To  prevent  broken 
glass  and  other  odds  and  ends  from  getting  from  the  sink  into 
the  sewer,  a  false  bottom  of  oak,  perforated  with  J  inch  holes 
should  be  provided.  To  prevent  the  pitch  from  running  out  of 
the  joints,  in  hot  weather,  it  is  safer  to  finish  off  the  joints  with  a 
final  layer  of  cement  plastered  firmly  on  top  of  the  pitch;  it  is 
absolutely  necessary  to  do  this  when  it  is  impossible  to  avoid 
placing  a  length  or  two  of  pipe  horizontally. 

The  elevation  of  the  balance  table  used  in  room  5  is  shown  in 
the  drawing  at  H  —  i,  Fig.  29-2,  page  411.  The  elevations  of 
the  hoods  and  tables  in  rooms  Nos.  4,  5  and  6  are  given  at 
A  -  i,  B  -  i,  C  -  i,  D  -  i,  E  -  i,  F  -  i,  G  -  i,  /  -  i  and 
J  —  i,  respectively  (see  Figs.  29-2-3). 

The  stone  tops  of  all  of  the  work  tables  are  covered  with  sheet 
rubber  packing  of  about  one-eighth  inch  thickness.  This  ma- 
terial makes  a  nice  appearance  and  prevents  considerable  break- 
age of  glassware. 


4i8 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


For  Water  Bottles 


Plate  Glass    H 

Plate  Glass 

IJi'Alberene 
/    Stone 

c 

4     U 

i 

1 

nt 
ctX 

HtVffi-2* 

1 

1          9 

nn: 

9 

? 

o 

o 

ij 

n  f 

I  —  sV—  J 

U*Hi'a^-  J 
—  *j 

|lHl_3'3^  * 
i  'm/'  

U*-3'3"—l 

^^"   ,       /h  —  2'io^-H 

2*^1— 


2-Tables  Req'd-D-1 


1 

2'S'- 

1 

0         ||          0 

"       II      ~ 

o 

O 

QD 

2 

i/\'-"^ 

r^2 

f-V^ 

IV'r  3  Stonft 

—  Ifi. 

1-Table  Req'd  -E ') 


-1 


0    II    0 

o        ||        c, 

1  J-  1 

:  ^  ,y     2M 

—  ,-*a 

—  5,^ 

=y 

1-Table  Req'd  —  G  ) 

1  "    -  rV» 


FIG.  29-3. 


CHAPTER   XX. 

PART  III. 

THE  MAKING  AND  REPAIRING  OF  LABORATORY  ELECTRIC 

FURNACES. 

IT  is  quite  an  economy  and  instructive  for  the  chemist  to 
build  and  repair  his  own  electric  muffle  and  combustion  fur- 
naces.* The  modern  laboratory  cannot  afford  to  be  without 
such  equipment.  The  author  uses  a  true  ni-chrome  wire  of 
German  manufacture.  For  the  carbon  combustion  furnaces, 
No.  20  gauge  wire,  0.032  diameter,  is  a  convenient  size.  Its 
resistance  is  0.537  ohm  per  foot.  With  a  voltage  ranging  as 
high  as  240,  direct  current,  90  feet  of  this  size  is  about  right 
and  gives  a  service  of  three  or  more  months,  running  24  hours 
per  day.  The  wire  is  coiled  around  a  -j%  diameter  rod  held  in 
guides  and  run  by  a  ^  horse  power  motor.  The  cost  of  a  rewir- 
ing is  as  follows: 

Wire $i .  oo 

Labor 0.75 

Clay  core 1.25 

Incidentals 0.25 

Total  $3.25 

The  expressage  is  saved  to  and  from  the  professional  repair- 
man and  the  delay  of  waiting  for  the  return  of  the  apparatus 
is  avoided. 

The  coiled  wire  is  wrapped  spirally  around  the  clay  core,  tak- 
ing precaution  that  the  turns  of  the  spiral  do  not  touch  each 
other  as  they  wind  around  the  core.  The  ends  of  the  coil  are  se- 
cured at  each  end  of  the  core  with  asbestos  cord,  being  tied  to  the 
latter.  The  turns  of  the  wire  are  then  covered  with  a  blanket 
of  alundum  cement.  The  core  is  put  in  a  warm  place  until  dry. 
At  each  end  of  the  coil  two  or  three  inches  of  the  wire  are  left 

*  The  author  ventilates  his  electric  muffle  furnaces  when  igniting  filter  papers, 
etc.,  by  blowing  a  regulated  stream  of  air  through  the  furnace. 

419 


420  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

uncoiled  for  connection  with  the  power.  One  of  the  cores  with  the 
wire  on  it  is  shown  in  Fig.  13,  page  242.  The  cement  is  plastered 
over  the  spiral  of  wire,  shown  in  the  figure.  The  chemist  can 
readily  follow  these  details  by  taking  such  a  furnace  apart.* 

A  large  muffle  furnace  can  be  built  by  any  laboratory.  A 
sheet  iron  frame  can  be  used  for  the  sides.  The  top  and  bottom 
of  the  shell  can  be  in  the  form  of  lids  of  the  same  material.  It 
is  well  to  place  at  the  top  and  bottom  of  each  corner  of  the 
frame,  and  on  the  inside  of  it,  right  angle  strips  of  hoop  iron. 
These  make  the  shell  more  rigid.  The  opening  for  the  muffle 
should  be  central  and  the  frame  or  shell  should  be  just  as  deep 
as  the  muffle  is  long,  so  that  the  muffle  will  rest  in  the  frame 
and  come  just  flush  with  the  outside  of  the  shell.  The  muffle 
opening  in  the  frame  should  fit  exactly  around  the  outside  of 
the  ends  of  the  muffle,  so  that  very  little  plastering  around  it 
with  the  cement  will  be  necessary.  The  writer  uses  No.  17 
gauge  wire  for  the  muffle  furnaces,  that  is,  0.045  mcn  diameter. 
Three  coils  are  wound  around  the  muffle  and  connected  in 
parallel.  The  writer  places  the  parallel  leads  on  the  outside  of 
the  furnace  shell,  thereby  keeping  the  leads  away  from  the  heat, 
and  more  accessible.  The  leads  are  enclosed  in  red  fiber  in- 
sulating tubes  and  supported  in  brass  brackets.  One  lead  is 
placed  on  the  right  side  of  the  furnace  shell  and  the  other  on 
the  left  side.  This  gives  a  neat  appearance.  Where  the  ends  of 
the  coils  pass  through  the  metal  shell,  they  are  carried  through 
small  quartz  or  pipe  clay  insulating  tubes  to  join  the  leads. 
Each  coil  is  120  feet  long  for  a  240  volt,  direct  current.  The 
heat  is  regulated  by  means  of  a  theater  dimmer  of  14  to  25  amps, 
capacity.  The  doors  are  sheet  iron,  lined  with  fire  brick.  They 
slide  up  and  downf  in  sheet  iron  guides  and  are  hung  on  a 

*  The  author  is  now  trying  the  plan  of  wiring  directly  on  his  tapered  clay  com- 
bustion tube.  This  gives  a  combustion  furnace  that  will  come  to  full  heat  in  30 
minutes,  and  saves  the  cost  of  the  core  tube. 

t  Or  the  door  can  be  made  to  open  on  side  hinges,  horizontally.  Such  a  door 
can  be  lined  with  a  fire  brick  that  fits  the  mufBe  opening  and  projects  into  the 
same.  This  liner  keeps  heat  in  better  than  one  that  slides  up  and  down.  The 
author  finds  it  convenient  to  mold  and  burn  his  own  liners. 


THE  MAKING  AND  REPAIRING  OF  LABORATORY,  ETC.     421 

lever.  The  leads  are  of  No.  8  gauge  ni-chrome  wire  of  the  same 
make  as  the  heating  wire.  The  furnace  shell  is  given  a  coat  of 
stovepipe  enamel  and,  if  preferred,  it  can  be  then  given  a  white 
finish  consisting  of  two  coats  of  aluminum  paint.  The  wire  for 
such  a  furnace  will  cost  $3.00;  the  clay  muffle  of  composite 
clay  is  the  most  durable  and  can  be  had  for  $3.50.  To  this 
should  be  added  one  day's  time  for  the  tinner  to  cut  out  the 
shell  and  the  cost  of  the  sheet  iron,  some  rivets,  bolts,  nuts, 
metal  washers,  fifty  pounds  of  magnesia  oxide  to  fill  in  all 
spaces  around  the  core  and  retain  the  heat.  The  entire  inside 


FIG.  36. 

of  the  shell  except  the  space  occupied  by  the  muffle  is  filled  with 
this  non-conducting  powder.  Four  right  angle  strips  of  sheet 
brass  about  £  inch  thick  will  be  needed  to  support  the  leads.  The 
whole  cost  is  a  mere  trifle  compared  to  the  price  one  must  pay 
for  such  a  furnace  made  to  order.  The  muffle  is  rectangular;  it 
is  8j  inches  X  6^  inches  X  14  inches.  The  furnace  shell  is  14 
inches  deep  to  fit  the  length  of  the  muffle.  It  is  i6j  inches  wide 
and  15  inches  high.  To  hold  such  a  furnace  at  any  desired  tem- 
perature from  200°  C.  to  1000°  C.  the  current  should  be  controlled 
with  a  dimmer  or  rheostat  of  from  at  least  12  to  2.5  amperes  and 
a  resistance  of  not  less  than  60  ohms. 


422  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

THE  NI-CHROME  ONE  PIECE  TRIANGLE. 

Fig.  36  shows  a  one  piece  triangle  designed  by  the  author 
which  any  one  can  make  in  a  few  minutes  from  the  well  annealed 
German  ni-chrome  wire.  It  is  practically  indestructible.  The 
one  shown  was  made  from  No.  8  gauge  wire. 

SANITARY  LABORATORY  WASH  BOTTLE. 

Fig.  37  shows  a  wash  bottle  that  is  much  used  in  this 
laboratory  for  washing  precipitates.  It  has  the  advantage  that 
the  lips  do  not  touch  it.  It  is  operated  by  a  slight  push  of  the 
thumb  on  the  rubber  bulb  A.  The  little  tube  at  P  enables 


FIG.  37. 

the  operator  to  instantly  relieve  pressure  when  a  washing  is 
finished,  avoiding  spattering  of  the  washing  fluid  and  excessive 
amounts  of  the  wash  per  application. 

The  rubber  bulb  is  attached  to  the  glass  tube  G.  The 
capacity  of  the  flask  is  500  c.c.  It  has  a  fire  finished  ring  neck 
and  takes  a  No.  6  rubber  stopper. 


CHAPTER   XXI. 
PART  I. 

AN  AUTOMATIC   STEAM  WATER  STILL. 

AFTER  submitting  to  considerable  annoyance  from  several 
types  of  water  stills,  the  author  decided  to  try  steam  coils  as  a 
source  of  heat. 

The  boiling  of  water  by  this  means  is  not  a  new  idea,  but  after 
more  than  a  year's  trial,  there  was  finally  evolved  a  form  of 
still  which  has  proven  so  satisfactory  and  the  flow  of  the  water 
has  been  so  abundant  that  the  details  of  the  apparatus  may  be 
of  assistance  to  someone  else. 

Two  of  these  stills  are  in  use  in  our  laboratory  operating  but 
part  of  each  day.  The  supply  is  ample  for  all  analytical  needs 
and  for  drinking  water,  which  is  also  furnished  to  a  large  office 
force. 

Cold  water  from  the  tap  enters  the  condenser  jacket  C,  Fig.  38, 
through  the  cock  A .  The  condenser  jacket  is  a  cylindrical  copper 
vessel  ii  inches  in  diameter  and  15  inches  high.  The  cooling 
water  overflows  at  B  to  a  sink  not  shown.  A  glass*  tube  siphon 
S',  S",  5/r/,  dipping  into  the  water  slightly  below  the  level  of  B, 
carries  hot  water  continually  to  the  heating  chamber  D  by  way 
of  the  large  copper  feed  funnel  Ff,  F" . 

When  the  water  in  D  has  risen  several  inches  the  steam  is 
turned  into  the  worm  coils  of  D  at  the  valve  V.  These  coils 
consist  of  two  1 2-foot  lengths  of  f  inch  bore  copper  pipe,f 
brazed  together  and  coiled  around  the  inside  walls  of  D.  The 
steam  from  the  boiling  water  rises  into  the  dome  and  passes 

*  A  brass  tube  is  now  used  as  it  is  more  durable. 

t  The  outside  diameter  of  the  copper  pipe  is  one  and  one-sixteenth  inches  and 
the  wall  is  one -eighth  inch. 

423 


424 


CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 


off  through  a  block  tin  condensing  pipe  of  f  inch*  inside  diam- 
eter at  T  and  travels  through  this  pipe,  which  is  coiled  in  a 
worm  as  shown  in  C. 

The  tin  pipe  passes  through  the  tubular  outlet  0',  0"  and 
delivers  the  distilled  water  on  a  filter  paper  supported  by  a  six 


FIG.  38. 

inch  ribbed  glass  funnel  W.  The  filter  papers  are  30  cm.  and 
are  folded  to  fit  the  funnel.  A  piece  of  cheese-cloth  is  folded 
in  the  apex  of  the  filter  paper  cone  to  prevent  the  weight  of  the 
water  from  breaking  the  paper.  The  filter  paper  catches  any 
oily  matter  or  other  particles  carried  over  with  the  steam. 

The  distillate  is  delivered  to  the  receiving  funnel  at  the  rate 
of  one  liter  every  3  minutes  when  sufficient  pressure  is  main- 

*  The  larger  the  inside  diameter  of  the  tin  worm  the  better  to  secure  rapid 
condensation  and  a  large  output  of  water. 

The  block  tin  worm  now  in  use  is  ff  to  i  inch  O.  D.;  |  to  ^  wall;  and  -g-f  bore. 
The  regular  commercial  sizes  approximating  these  dimensions  are  used.  A  num- 
ber of  these  stills  are  now  in  use. 


AN  AUTOMATIC   STEAM   WATER   STILL  425 

tained  in  D  to  keep  the  copper  funnel  F',  F"  filled  nearly  to 
overflowing  with  hot  water. 

The  water  reservoir  is  a  nine  gallon  bottle,  in  the  neck  of 
which  the  funnel  W  rests.  The  bottle,  which  is  not  shown, 
is  inclosed  in  a  cupboard  in  which  is  an  electric  light  to  dispel 
darkness  and  roaches.  This  bottle  rests  in  a  copper  pan,  which 
is  drained  to  the  sewer.  The  tin  pipe  is  bent  into  an  elbow  at 
E  so  that  any  condensation  of  moisture  on  damp  days  drips  off 
at  E  instead  of  running  down  the  pipe  into  W. 

Steam  pressure  furnished  from  the  mills  is  liable  to  continual 
variation.  The  amount  of  pressure  may  be  nicely  adjusted  at 
F,  but  subsequent  increase  of  pressure  often  causes  the  water  to 
boil  over  at  F  and  splash  down  into  the  copper  pan  P',  P",  Pr", 
which  is  drained  at  P' .  The  pan  is  five  inches  deep  and  large 
enough  to  contain  the  entire  apparatus. 

To  clean  the  still  the  tin  pipe  is  unscrewed  at  N,  the  dome 
head  is  removed,  and  water  is  played  on  the  interior  of  D  with  a 
hose,  washing  the  sediment  out  through  the  cock  at  P'" . 

The  steam  dome  rests  in  the  neck  of  D  and  is  calked  steam 
tight  with  cheese-cloth.  The  cloth  is  stretched  in  a  dia- 
phragm across  R',  R"}  with  enough  excess  of  cloth  for  calking 
purposes. 

The  boiling  of  the  water  in  F',  F"  in  no  way  prevents  the 
action  of  the  siphon  S',  S",  5"".  The  heating  coils  of  D  are 
joined  to  ordinary  steam  pipes  of  the  same  diameter  at  /',  J" . 

This  still  could  be  made  in  any  size  to  suit  a  greater  or  less 
production  than  that  mentioned,  a  smaller  size  for  a  household 
or  small  laboratory,  and  in  larger  sizes  for  office  buildings  or 
for  manufacturers  needing  a  large  supply  of  distilled  water.  A 
number  of  these  stills  are  now  in  use. 


CHAPTER   XXI. 

PART  II. 
CLAY  COMBUSTION  BOATS. 

THE  clay  boats  are  made  from  Klingenberg  clay.*  A  typical 
analysis  of  it  is  given  herewith: 

Per  cent. 

Protoxide  of  iron 2.67 

Silica . 52 . 48 

Alumina 29 . 46 

Ignition  loss 14. 18 

Any  plastic  clay  free  from  grit  would  answer  just  as  well. 
The  clay  is  ground  to  pass  a  30-mesh  sieve,  and  is  thoroughly 
kneaded  to  a  stiff  dough  with  water.  It  is  then  rolled  in  a  towel. 
By  wetting  the  towel  occasionally,  the  clay  can  be  kept  ready 
to  use  as  long  as  desired. 

The  clay  is  rolled  on  a  moist  plaster-of-paris  slab  into  a  cigar 
shape  and  pressed  into  the  plaster-of-paris  mold  with  the  thumbs. 
The  excess  clay  is  scraped  off  with  a  thin-edged  piece  of  wood. 
The  guide  strip  is  then  laid  on  the  mold.  It  is  the  exact  dupli- 
cate of  the  face  of  the  mold,  or  pmno  as  shown  in  the  plan.  This 
strip,  of  course,  has  an  opening  in  it  coinciding  exactly  with 
IcdJ,  Fig.  39.  The  strip  can  be  fastened  on  by  a  gum  band  at 
each  end.  The  wooden  tool  T  is  plunged  down  through  this  slot, 
and,  while  being  held  perfectly  vertical,  it  is  slid  along  the  wooden 
guide  strip,  scooping  out  the  clay  and  shaping  the  interior  of 
the  boat.  The  tool  slides  along  the  strip  on  its  surfaces  at  R 
and  R'.  The  distances  from  c'  to  R  and  from  Rf  to  df  are  equal 
and  conform  to  the  thickness  of  the  guide  strip.  The  distance 
c'd'  equals  cd.  c'V  and  V'd'  regulate  the  thickness  of  the  walls 
of  the  boat.  VfV  forms  the  interior  of  the  boat.  The  tool  T  is 
rounded  on  one  side  and  is  trimmed  to  a  thin  edge  on  the  rounded 

*  A  blend  of  clays  gives  better  results. 
426 


CLAY  COMBUSTION  BOATS 


427 


side.  The  tools  are  kept  in  water,  when  not  in  the  operator's 
hand,  to  prevent  the  clay  from  sticking  to  them.  The  interior 
of  the  mold  has  a  flat  bottom.  The  author  prefers  a  boat  of 
the  following  outside  dimensions  when  burned:  15  mm.  wide  at 


\ 


FIG.  39. 

top  by  7  mm.  wide  at  bottom  by  9  mm.  high  by  13  ij  mm.  long. 
The  bowl  of  the  mold  should  be  about  6  per  cent  larger  in  all 
its  dimensions  to  allow  for  shrinkage. 

After  the  interior  has  been  properly  shaped,  the  guide  strip 
is  removed,  the  face  of  the  mold  scraped  clean,  and  the  mold  put 
away  in  a  warm  place  for  the  clay  to  dry.  Slow  drying  for  one 
or  two  days  is  the  best.  When  the  boats  no  longer  seem  damp 
to  the  touch,  they  are  removed  from  the  molds  and  dried  for 
several  hours  in  an  air  bath  at  a  temperature  of  120°  C.  They 
are  then  put  in  a  muffle  furnace,  and  the  latter  is  lighted  and 


428  CHEMICAL  ANALYSIS  OF  SPECIAL  STEELS 

the  heat  brought  as  quickly  as  convenient  to  a  temperature  of 
850°  to  900°  C.  (very  bright  red-heat)  and  kept  at  that  tem- 
perature for  from  two  to  four  hours.  The  heat  is  then  turned 
off  and  the  boats  are  ready  for  use.  A  boy  can  easily  mold 
forty  boats  in  three  hours,  and,  after  the  molding  is  completed, 
the  remaining  operations  require  but  a  few  moments'  attention 
to  make  the  transfers  from  the  drying  space  to  the  air  bath,  and 
from  the  latter  to  the  muffle  furnace. 

The  boat  should  have  walls  and  bottoms  about  -j1^  inch  thick. 
Boats  made  as  described  answer  all  of  the  purposes  of  porcelain 
boats,  and,  one  can  readily  see,  are  extremely  cheap.  The 
writer  first  experimented  with  a  view  to  making  his  own  boats, 
more  than  4  years  ago,  and  now  uses  them  for  all  combustion 
work. 

It  is  convenient  to  have  the  dimension  Kh,  62  mm.;  hg,  177 
mm.,  and  the  total  thickness  of  the  mold  25  mm. 

When  the  boats  have  been  burned,  two  or  three  from  each 
batch  should  be  placed  in  the  combustion  furnace  and  a  blank 
analysis  made.  If  the  weighing  apparatus  shows  a  gain  of  more 
than  0.0002  gram,  it  is  an  indication  of  imperfect  burning  of  the 
boats.  They  should  be  reburned  until  free  from  all  carbonaceous 
matter. 

The  author  wishes  to  acknowledge  the  assistance  and  advice 
rendered  him  by  the  superintendent  of  the  plumbago  crucible 
factory  of  this  works,  Mr.  Bayard  Guthrie,  in  working  out  the 
method  of  making  a  cheap  substitute  for  porcelain  combustion 
boats. 


INDEX 


PAGE 

Atomic  weights:  See  back  cover. 

Acid  in  oils 392 

Acid  and  ammonia,  reduction  of,  to  lower  per  cents 404 

Annealing: 

of  plain  carbon  steel 339 

of  Hadfeld's  steel 340 

of  chrome-manganese  steel 347 

of  nickel  steel 347 

chemical  test  for 344 

of  overheated  steel 341 

bark  formation  by  annealing 348 

formation  of  graphitic  carbon  by  annealing 342 

Aluminum: 

determination  of,  in  crucible  slag 113 

in  ferro- vanadium 18,  23,  26 

in  ferro-titanium 45,  52,  59 

in  f erro-chromium 138,  139, 143 

in  nickel-chromium  alloy 180 

in  iron  ore 371 

in  chrome  cement 144 

in  graphite  crucibles 322 

in  steel 146,  148 

Ash: 

determination  of,  in  coal 399 

in  coke 403 

Boats,  clay  combustion 426 

Bath,  graphite 98,  415 

Bark,  formation  of,  in  steel 348 

Bismuth,  determination  of,  in  steel 134 

Carbon,  determination  of: 

in  coke 403 

in  coal 399 

in  graphite  crucibles 329 

in  ferro-chromium ^7 

in  ferro-titanium ^x 

in  ferro-manganese 192 

429 


430  INDEX 

PAGE 

Carbon,  determination  of: 

in  ferro- vanadium 14 

in  molybdenum  powder 115 

in  tungsten  powder 71 

in  nickel-chromium  alloy 180 

in  steel  by  color 252 

in  steel  by  solution  in  double  chloride  of  copper  and  potassium 246 

in  steel  by  direct  combustion  in  oxygen,  heating  with  gas  and  blast 23  2 

in  steel  by  direct  combustion  with  red  lead 203 

in  steel  by  direct  combustion  in  the  electrically  heated  furnace 224 

Carbon  dioxide,  determination  of: 

in  fluorspar 380 

in  iron  ore 373 

Calcium,  determination  of: 

in  limestone 357 

in  graphite  crucibles 333 

in  fluorspar 383 

in  iron  ore 371 

in  titanium  slag 66 

volumetric  determination  of  calcium 359 

Calcium  fluoride,  determination  of,  in  fluorspar 377 

Calcium-electrosilicon,  analysis  of 289 

Chromium: 

qualitative  test  for,  in  steel i,  345 

determination  of,  in  chrome-vanadium  steel 38,  39, 148 

in  chrome-tungsten  steel 109 

in  chrome-nickel  alloy 179 

in  ferro-chromium 136,  142 

in  ferro-vanadium 31 

in  ferro-titanium 51 

in  iron  ore 373 

in  stellite 322 

Chromic  oxide,  determination  of: 

in  chrome  ore 140 

in  chrome  cement 145 

in  crucible  slag 112 

Cinchonine  solution 109 

Clay  combustion  boats 426 

Clay  combustion  tubes  with  tapered  end 243 

Cobalt: 

determination  of,  qualitatively 303 

in  steel,  volumetrically 307 

in  steel,  gravimetrically : 3°4 

in  cobalt  metal,  gravimetrically 3°4,  3°7 

in  cobalt  metal  by  electrolysis 316 

Cold  test  in  oils.  .                                        392 


INDEX  431 

PAGE 

Copper: 

qualitative  test  for,  in  steel 151 

quantitative  determination  of,  in  steel  and  iron 152 

in  iron  ore : 373 

in  Monel  metal 183 

in  molybdenum 120 

in  ferro-vanadium 154 

in  metallic  copper 157 

Crucible  slag,  analysis  of no 

Decarbonization  of  steel 348 

Distillation  of  water 423 

Furnace: 

electric  muffle 420 

electric  combustion  furnace 414,  419 

gas  furnace  for  evaporation,  etc 363 

gas  furnace  for  carbon  combustions 231 

Ferro-chrome,  analysis  of 136 

Ferro-manganese,  analysis  of 188 

Ferro-molybdenum,  analysis  of 122 

Ferro-phosphorus,  analysis  of 265 

Ferro-silicon,  analysis  of 191 

Ferro-titanium,  analysis  of 43 

Ferro-tungsten-molybdenum 124 

Ferro-vanadium 4 

Ferro-uranium • 289 

Flash  point  of  oils 391 

Fire  test  of  oils 391 

Fluorspar,  analysis  of 375 

Fire  brick 360 

Ferricyanide  solutions: 

indicator  for  vanadium  in  steel 10 

indicator  for  titration  of  iron 369 

Graphite: 

determination  of,  in  iron  and  steel 259 

determination  of,  in  graphite  crucibles 329 

Hoods  for  the  carrying  away  of  fumes 411,  413,  415 

Heat  units  in  coal 400 

Iron,  determination  of: 

in  iron  ore 367 

in  ferro-phosphorus 268 

in  ferro-manganese 192 

in  ferro-chrome 140 


432  INDEX 

PAGE 

Iron,  determination  of: 

in  ferro-molybdenum 126 

in  ferro- vanadium 28 

in  ferro-titanium 47,  52,  59 

in  ferro-silicon 192 

in  f erro-uranium 290 

in  molybdenum  powder 118 

in  Monel  metal 186 

in  nickel-chrome  alloy 180,  181 

in  tungsten  powder 70,  72 

Iron  oxide,  determination  of: 

in  chromium- tungsten  slag in 

in  basic  slag  containing  titanium 64 

Lead,  determination  of,  in  fluorspar 379 

Limestone,  analysis  of 356 

Magnesia,  determination  of: 

in  limestone  and  magnesite 357 

in  graphite  crucibles 333 

in  fluorspar 379 

in  iron  ore 372 

in  titanium  slag 66 

in  chrome-tungsten  slag in 

Magnesite,  analysis  of 356 

Manganese,  determination  of: 

in  ferro-manganese,  gravimetric 188 

in  ferro-manganese,  by  Volhard  method 192 

in  ferro-manganese,  by  potassium  ferricyanide 193 

in  ferro-chromium 14° 

in  ferro-silicon I91 

in  ferro-titanium 41,  52 

in  ferro-vanadium I5J  X6 

in  cobalt  steel 321 

in  crucible  slag "4 

in  titanium  slag 65 

in  iron  ore 37° 

in  tungsten  powder 71 

in  nickel-chromium  alloy 180 

in  steel 276,  278,  281,  283 

in  stellite 322 

in  molybdenum  powder , 120 

Milling  machine 220 

Moisture: 

in  coal 398,  399 

in  iron  ore 373 


INDEX  433 

PAGE 

Molybdenum,  determination  of: 

in  f erro-molybdenum 125 

in  ferro-vanadium 32 

in  molybdenum  powder 115,  116,  118 

in  steel,  qualitative 2 

in  steel,  quantitative 130,  132,  133 

in  ore 128 

in  stellite 322 

in  tungsten  powder 71 

Nickel,  qualitative  test  for 3 

determination  of,  in  cobalt  metal  by  electrolysis 316 

in  cobalt  steels 311 

in  the  presence  of  much  cobalt 314 

in  ferro-titanium 51 

in  ferro-vanadium 14 

Nickel: 

in  iron  ore 373 

in  Monel  metal 185 

in  nickel-chromium  alloy 178 

in  steel  by  the  cyanide  method 164 

in  steel  by  Brunck's  method 175 

in  steel  by  a  modification  of  Brunck's  method 175 

in  steel  by  electrolysis 316 

Nessler  solution 327 

Nitrogen  in  steel 324 

Normal  solution 387 

Oxygen  in  steel 82 

in  tungsten  powder 74 

Oils,  testing  of  lubricating  oils 385 

Plan  of  laboratory 410,  411 

Percentage  reduction  of  acids 404 

Phosphorus,  determination  of: 

in  coal 402 

in  crucibles 332 

in  cobalt  metal 320 

in  crucible  slag 114 

in  ferro-chromium 138,  139, 

in  ferro-manganese igo 

in  ferro-molybdenum 1 24 

in  ferro-phosphorus 265 

in  ferro-titanium 45 

in  ferro-vanadium 20,  23,  24 

in  iron  ore 370, 


434  INDEX 

PAGE 

Phosphorus,  determination  of: 

in  steel , 257 

in  vanadium  steel 264 

in  tungsten  ore 84 

in  tungsten  oxide 86 

in  f erro-tungsten 83 

in  tungsten  powder 70,  86 

in  titanium  slag 67 

Sampling: 

of  hard  and  soft  layers „ 222 

by  milling 221 

by  drilling 218,  219 

Sand: 

complete  analysis  of 360 

use  of,  in  combustion  boats 241 

Saponification  number  of  oils 385 

Silica,  determination  of: 

in  chrome  cement 144 

in  crucible  slag no 

in  limestone 356 

in  iron  ore 370 

in  fluorspar 378 

in  molybdenum  powder .' 115 

in  sand 360 

in  tungsten  powder 72 

in  titanium  slag 64 

Silicon,  determination  of: 

in  cobalt , 320 

in  ferro-chrome 140 

in  f  erro- manganese 188 

in  ferro-molybdenum 123 

in  ferro-molybdenum-tungsten 124 

in  ferro-silicon 191 

in  ferro-titanium 50,  51 

in  ferro- vanadium 33 

in  Monel  metal 183 

in  steel  and  pig  iron 285 

in  stellite 322 

Silicon  carbide,  determination  of,  in  graphite  crucibles 335 

Segregation,  test  for,  in  steel 223 

Sink,  of  stoneware 4*6 

Specific  gravity : 

of  ammonia 4°9 

of  nitric  acid 40?,  408 

Stellite,  analysis  of 322 


INDEX  435 

PAGE 

Still,  steam  still  for  distillation  of  water 423 

Sulphur,  determination  of: 

in  coal 400,  401 

in  coke 403 

in  cobalt  metal 320 

in  ferro-chrome 138,  139 

in  ferro-manganese 192 

in  ferro-silicon  and  metallic  silicon 192 

in  ferro-molybdenum „  126 

in  ferro-titanium 45 

in  ferro-vanadium 17 

in  ferro-phosphorus 268 

in  molybdenum  powders 119 

in  Monel  metal 187 

in  steel,  gravimetric,  plain  steel 274 

in  steel,  volumetric,  plain  steel 269 

in  steel,  gravimetric,  for  alloy  steels 102 

in  alloy  steels  by  evolution  with  acid-carrying  hydrogen  at  a  yellow  heat. .  104 

in  fluorspar 380 

in  graphite  crucibles 337 

in  titanium  steel 53 

in  iron  ore 371 

Surface  decarbonization 81,  241 

Standardization: 

of  double  sulphate  of  iron  and  ammonium: 

for  vanadium 41 

for  chromium 41 

of  permanganate  of  potassium: 

for  iron  and  manganese 49 

for  vanadium  in  steel 33,  40 

for  small  amounts  of  iron  in  crucibles 336 

for  iron  in  iron  ore 368 

for  uranium 294,  295,  296 

of  potassium  dichromate: 

for  small  amounts  of  iron 186 

for  iron  ore 369,  370 

of  potassium  cyanide: 

for  copper  in  metallic  copper 158 

for  copper  in  Monel  metal 184 

for  nickel  in  Monel  metal 185 

for  nickel  in  steel 167 

Titanium,  determination  of : 

in  ferro-titanium 53,  57,  60 

in  fire  brick 366 

in  iron  ore . . .  v 372 


INDEX 

PAGE 

Titanium,  determination  of: 

in  plain  titanium  steel 53,  54,  60 

in  vanadium-titanium  steel 56,  62,  63 

in  chrome-vanadium-nickel-titanium  steel. 62 

in  nickel  steel 62 

Tin: 

determination  of,  in  steel 134 

in  tungsten  powder 86 

Tubes,  tapered  clay  combustion  tubes 243 

Tungsten: 

qualitative  test  for,  in  steel .  I 

determination  of,  in  steel 98,  108,  129,  130 

in  ferro-tungsten-molybdenum 124 

in  tungsten  ores 92 

in  tungsten  powder 68,  69 

in  molybdenum  powders 119 

Triangle,  one  piece  triangle  of  true  ni-chrome  wire 421 

Tables,  laboratory  work  tables 411,  417,  418 

Uranium: 

determination  of,  in  steel 148,  299 

in  ferro-uranium 289 

in  ores 289 

qualitative  test  for 299 

Vanadium,  determination  of: 

in  steel 7,  13,  37,  39,  148 

in  chrome-tungsten  steel 109 

in  ferro- titanium 51 

in  ferro- vanadium 10,  35 

in  ores,  carnotite,  roscoelite,  patronite 301 

in  iron  ore 374 

Viscosity  of  oils ' 393 

Volatile  matter  in  coals 399 

in  graphite  crucibles 329 

Wash  bottle,  sanitary 422 


INTERNATIONAL  ATOMIC  WEIGHTS,  1914. 


Elements. 

Atomic 

Weights. 

Elements. 

Atomic 
Weights. 

Symbol. 

Symbol. 

Aluminium 

Al 

27.1 

Molybdenum 

Mo 

96.0 

Antimony 

Sb 

120.2 

Neodymium 

Nd 

144-3 

Argon 

A 

39-88 

Neon 

Ne 

20.2 

Arsenic 

As 

74.96 

Nickel 

Ni 

58.68 

Barium 

Ba 

137-37 

Niton  (radium  ema-  Nt 

222.4 

Bismuth 

Bi 

208.0 

nation) 

Boron 

B 

II  .O 

Nitrogen 

N 

I4.OI 

Bromine 

Br 

79.92 

Osmium 

Os 

190.9 

Cadmium 

Cd 

II2.4 

Oxygen 

O 

16.00 

Caesium 

Cs 

I32.8I 

Palladium 

Pd 

106.7 

Calcium 

Ca 

40.07 

Phosphorus 

P 

3I-04 

Carbon 

C 

12.  OO 

Platinum 

Pt 

195-2 

Cerium 

Ce 

140..  25 

Potassium 

K 

39.10 

Chlorine 

Cl 

35-46 

Praseodymium 

Pr 

140.6 

Chromium 

Cr 

52.0 

Radium 

Ra 

226.4 

Cobalt 

Co 

58.97 

Rhodium 

Rh 

102.9 

Columbium 

Cb 

93-5 

Rubidium 

Rb 

85-45 

Copper 

Cu 

63-57 

Ruthenium 

Ru 

101.7 

Dyprosium 

Dy 

162.5 

Samarium 

Sa 

150-4 

Erbium 

Er 

167.7 

Scandium 

Sc 

44.1 

Europium 

Eu 

152.0 

Selenium 

Se 

79.2 

Fluorine 

F 

19.0 

Silicon 

Si 

28.3 

Gadolinium 

Gd 

157-3 

Silver 

Ag 

107.88 

Gallium 

Ga 

69.9 

Sodium 

Na 

23.00 

Germanium 

Ge 

72-5 

Strontium 

Sr 

87.63 

Glucinum 

Gl 

9.1 

Sulphur 

S 

32.07 

Gold 

Au 

197.2 

Tantalum 

Ta 

181.5 

Helium 

He 

3-99 

Tellurium 

Te 

127.5 

Holmium 

Ho 

163.5 

Terbium 

Tb 

159-2 

Hydrogen 

H 

i.  008 

Thallium 

Tl 

204.0 

Indium 

In 

114.8 

Thorium 

Th 

232.4 

Iodine 

I 

126.92 

Thulium 

Tm 

168.5 

Iridium 

Ir 

I93-1 

Tin 

Sn 

119.0 

Iron 

Fe 

55-84 

Titanium 

Ti 

48.1 

Krypton 

Kr 

82.92 

Tungsten 

W 

184.0 

Lanthanum 

La 

139.0 

Uranium 

u 

238.5 

Lead 

Pb 

207.10 

Vanadium 

V 

51-0 

Lithium 

Li 

6.94 

Xenon 

Xe 

130.2 

Lutecium 

Lu 

174.0 

Ytterbium 

Yb 

172.0 

Magnesium 

Mg 

24.32 

Yttrium 

Yt 

89.0 

Manganese 

Mn 

54-93 

Zinc 

Zn 

65-37 

Mercury 

Hg 

200.6 

Zirconium 

Zr 

90.6 

Reprinted  from  the  Journal  of  the  American  Chemical  Society. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 


Return  to  desk  from  which  borrowed. 

This  book  is  DUE  on  the  last  date  stamped  below. 
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OCT4     1955 
AN   ,6   ;  56 


LD  21-100wi-ll,'49(B7146sl6)476 


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